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Transcriber Note

To preserve cross-references between the volumes, both have been
combined into one. Text emphasis denoted by _Italics_. Whole and
fractional parts of numbers displayed as 123-4/5.

                                  THE

                          Medals of Creation;

                                  OR,

                       FIRST LESSONS IN GEOLOGY,

                                  AND

                     THE STUDY OF ORGANIC REMAINS.

                               VOL. I.

"If we look with wonder upon the great remains of human works, such
as the columns of Palmyra, broken in the midst of the desert; the
temples of Pæstum, beautiful in the decay of twenty centuries; or the
mutilated fragments of Greek sculpture in the Acropolis of Athens,
or in our own museums, as proofs of the genius of artists, and power
and riches of nations now past away; with how much deeper feeling of
admiration must we consider those grand monuments of nature which
mark the revolutions of the Globe; continents broken into islands;
one land produced, another destroyed; the bottom of the ocean become
a fertile soil; whole races of animals extinct, and the bones and
exuviæ of one class covered with the remains of another; and upon the
graves of past generations--the marble or rocky tombs, as it were, of
a former animated world--new generations rising, and order and harmony
established, and a system of life and beauty produced out of chaos and
death; proving the infinite power, wisdom, and goodness of the Great
Cause of all things!"--Sir H. Davy.

[Illustration: _Pl. 1._

  _J. Dinkel del. G. Scharf lithog._  _Printed by Hullmandel & Walton_

                        MEDALS OF CREATION]

                                THE

                        Medals of Creation;

                                OR,

                     FIRST LESSONS IN GEOLOGY,

                                AND

                   THE STUDY OF ORGANIC REMAINS.

                                BY

          GIDEON ALGERNON MANTELL, LL.D. F.R.S. V.P.G.S.

 PRESIDENT OF THE WEST LONDON MEDICAL SOCIETY, ETC. AUTHOR OF THE
                     WONDERS OF GEOLOGY, ETC.

"Voilà! une nouvelle espèce de médailles, beaucoup plus importantes,
et incomparablement plus anciennes, que toutes celles des Grecs et des
Remains!"--Knorr, _Monumens des Catastrophes_.

                       IN TWO VOLS.--VOL. 1.

                            CONTAINING

       Fossil Vegetables, Zoophytes, Echinoderms, and Molluscs.

                SECOND EDITION, ENTIRELY REWRITTEN.

                              LONDON:

            HENRY G. BOHN, YORK STREET, COVENT GARDEN.

                             MDCCCLIV

                              LONDON:

               R. CLAY, PRINTER, BREAD STREET HILL.

                                TO

                             MY SONS,

                          WALTER MANTELL,

                    OF WELLINGTON, NEW ZEALAND,

                                AND

                     REGINALD NEVILLE MANTELL,

                    OF KENTUCKY, UNITED STATES,

                               This Work

            MY LAST ATTEMPT TO PROMOTE THE ADVANCEMENT

                     OF SCIENTIFIC KNOWLEDGE,

                 IS MOST AFFECTIONATELY INSCRIBED.

                             G. A. M.

  Chester Square, Pimlico,
  _Feb. 3, 1853_.

[The above having been penned by the much-lamented author of the
"Medals" some months previous to his decease, it is retained in this
posthumous edition of his favourite work as an appropriate dedication,
dictated by the parental affection of one of the chief promoters of
geological science in England, and addressed to his absent sons, whose
works have already shown them to be enthusiastic labourers in the same
field, both at home and in distant parts of the world.]

PREFATORY NOTE TO THE SECOND EDITION.

The untimely Decease of the lamented Author of the "Medals of Creation"
during the progress of the present edition through the press has
unavoidably delayed its publication.

The First Volume has been wholly rewritten by the Author.

The materials of the Second Volume had been elaborately revised and
much enlarged by Dr. Mantell previously to his Decease. The Editor
has laboured to carry out the intentions of the Author in rendering
this part of the Work as complete a compendium as possible of the
Palæontological history of the Organic Beings of which it treats, and
in adapting it to the requirements of the Geological Student of the
present time.

The various sources from which palæontological and zoological
information has been derived have, for the most part, been adverted to
in the text or in the footnotes. The Editor, however, has especially
to acknowledge the kindness of Mr. J. Morris, F.G.S., in allowing
him to refer to the proof-sheets of the forth-coming edition of his
"Catalogue of British Fossils," and thereby affording him important
assistance in making correct statements of the distribution of the
Fossil Remains of the Crustacea, Insecta, and Vertebrata, in the strata
of the British Islands.

  T. Rupert Jones.

PREFACE TO THE FIRST EDITION.

In the first edition of the Wonders of Geology, an intention was
expressed of immediately publishing, as a sequel to those volumes,
"First Lessons," or an Introduction to the Study of Petrifactions, for
persons wholly unacquainted with the nature of Fossil Remains; but the
completion of the contemplated work was unavoidably postponed, from
year to year, by the long and severe indisposition of the Author.

In the meanwhile several works professing the same object have issued
from the press; and an enlarged edition of Sir C. Lyell's "Elements"
has also appeared, in which the elementary principles of physical
Geology are fully illustrated, and numerous figures given of the
characteristic fossils of the several formations, or groups of strata.
But that department of the science which especially treats of Organic
Remains is necessarily considered in a cursory manner; and a work
upon the plan originally contemplated by the Author seems still to be
required, to initiate the young and uninstructed in the study of those
Medals of Creation--those electrotypes of nature--the mineralized
remains of the plants and animals which successively flourished in the
earlier ages of our planet, in periods incalculably remote, and long
antecedent to all human history and tradition.

With this conviction the present volumes are offered, with such
modifications of the original plan as circumstances have rendered
necessary, as a guide for the Student and the Amateur Collector of
fossil remains; for the intelligent Observer who may desire to possess
a general knowledge of the subject, without intending to pursue
Geology as a science; and for the Tourist who may wish, in the course
of his travels, to employ profitably a leisure hour in quest of those
interesting memorials of the ancient physical revolutions of our globe,
which he will find everywhere presented to his observation.

Crescent Lodge, Clapham Common, _May_, 1844.

ADDRESS TO THE READER.

"Some books are to be tasted--others to be swallowed--and some few to
be chewed and digested; that is, some Books are to be read only in
parts--others to be read, but not curiously--and some few to be read
wholly and with diligence and attention."--Lord Bacon's Essays.

Anxious that the "Courteous Reader" should derive from this work all
the information it is designed to impart, the Author presumes to
offer a few words in explanation of the plan upon which it has been
constructed, and some suggestions as to the best means of rendering its
contents most available to the varied tastes and pursuits of different
classes of readers.

In its arrangement, a three-fold object was had in view; namely, in the
first place, to present such an epitome of Palæontology, the science
which treats of the fossil remains of the ancient inhabitants of the
Globe, as shall enable the intelligent Observer to comprehend the
nature of the principal discoveries in modern Geology, and the method
of investigation by which such highly interesting, and unexpected
results, have been obtained..

Secondly, to assist the Collector in his search for Organic
Remains,--directing attention to those objects which possess
the highest interest, and are especially deserving of accurate
examination--instructing him in the art of developing and preserving
the specimens he may discover--and pointing out the means to be
pursued, for ascertaining their nature, and their relation to existing
plants or animals.

Thirdly, to place before the Student a familiar exposition of the
elementary principles of Palæontology, based upon a general knowledge
of the structure of vegetable and animal organization; to excite in his
mind a desire for further information, and prepare him for the perusal
and study of works of a higher order than these unpretending volumes;
and to point out the sources from which the required instruction may be
derived.

Although fully aware of the imperfect manner in which these intentions
are fulfilled, the Author hopes that the indulgence claimed by one of
the most able writers of our times may be extended to him; and that,
"if the design be good upon the whole, the work will not be censured
too severely for those faults, from which, in parts, its very nature
would scarcely allow it to be free."[1]

[1] Sir E. B. Lytton--preface to the second edition of "The Disowned."

With regard to the best means of making use of these volumes, the
advice of the great founder of Inductive Philosophy, on the Study of
Books in general, expressed in the quotation prefixed to this address,
is peculiarly applicable to the different classes of readers for whom
the work is designed.

Thus, "_the Book may be tasted, that is, read only in parts_," by the
intelligent reader, who requires but a general acquaintance with the
subjects it embraces. The perusal of the introductory and concluding
remarks of each chapter, of the general descriptions of fossil
remains, and of the circumstances under which they occur,--omitting the
scientific terms and descriptions,--and a cursory examination of the
illustrations, will probably satisfy his curiosity; and the work may
be transferred to the library for occasional reference, or taken as a
travelling companion and guide to some interesting geological district.

But the Book "_must be swallowed, that is, read, but not curiously_,"
by the reader desirous of forming a collection of organic remains. A
general acquaintance with its contents, and a careful investigation
of the characters of the fossils, and comparison with the figures and
descriptions, will be requisite to enable the amateur collector to
determine the nature of the specimens he may discover.

By the Student the Book "_must be digested, that is, read wholly, and
with diligence and attention_." He should fully comprehend one subject
before he advances to the consideration of another, and should test
the solidity of his knowledge by practical research. He should visit
some of the localities described; collect specimens, and develope
them with his own hands; examine their structure microscopically;
nor rest satisfied until he has determined their general characters,
and ascertained their generic and specific relations. Nor is this an
arduous or irksome task; by a moderate degree of attention, a mind
of average ability may quickly overcome the apparent difficulties,
and will find in the knowledge thus acquired, and in the accession of
mental vigour which such investigations never fail to impart, an ample
reward for any expenditure of time and trouble.

It is, indeed, within the power of every intelligent reader, by
assiduity and perseverance, to attain the high privilege of those who
walk in the midst of wonders, in circumstances where the uninformed and
uninquiring eye can perceive neither novelty nor beauty; and of being

                       "Even as one,
      Who by some secret gift of soul or eye,
    In every spot beneath the smiling sun.
      _Sees where the Springs of living Waters lie!_"

                          TABLE OF CONTENTS.

                               ~~~~~~~~

                                VOL. I.

  Dedication, p. v.

  Prefatory Note to the Second Edition, vii.

  Preface to the First Edition, ix.

  Address to the Reader, xi.

  Table of Contents, xv.

  Description of the Plates, xix.

  List of Lignographs in Vol. I., xxxi.

  Introduction, 1.

  Preliminary Remarks:--On the Plan of the Work and the Arrangement and
    Subdivision of the subjects it embraces, 8. Works of Reference, 8.
    Explanation of Terms, 11. List of subjects, 12.

    PART I.--Stratigraphy of the British Islands, and the Nature of
                             Fossils, 15.

  Chapter I.--On the Nature and Arrangement of the British Strata and
    their Fossils, 15.

  Chapter II.--Synopsis of the British Strata, 23. Chronological
    Arrangement of the British Formations; Modern or Human Epoch;
    Post-Pliocene, 23. Tertiary Epochs, 24. Secondary Epochs, 25.
    Palæozoic Epochs, 30. Hypogene Rocks, 34. Volcanic Rocks, 35.

  Chapter III.--On the Nature of Fossils or Organic Remains, 37.
    Incrustations, 38. Silicification, 40. Animal Remains, 43. Hints
    for Collecting Fossil Bones, 45.

                     PART II.--Fossil Botany, 51.

  Chapter IV.--Fossil Botany, 51. Fossil Vegetables, 51. On the
    investigation of the Fossil Remains of Vegetables, 54. Endogenous
    Stems, 56. Exogenous Stems, 56. Structure of Coniferæ, 57.
    Botanical principles, 58. Exogens, 59. Endogens, 59. Investigation
    of Fossil Stems, 61. Fossil Leaves, 64. On the Microscopical
    Examination of Fossil Vegetables, 65. Mode of preparing slices of
    Fossil Wood, 66.

  Chapter V.--On Peat-wood, Lignite, and Coal, 69. Submerged Forests;
    Peat, 70. Lignite, Brown-coal, Cannel-coal, 71. Bovey-coal,
    72. Jet, 72. Wealden Coal, 73. Coal, 76. Stratification of a
    Coal-field, 80. Origin and Nature of Coal, 82.

  Chapter VI.--Fossil Vegetables, 86. Fossil Cryptogamia, 87. Recent
    Diatomaceæ, 88. Fossil Diatomaceæ, 93. Fossil Coniferæ, 100. Fossil
    Fucoids, 101. Chondrites, 101. Moss-agates and Mocha-stones, 103.
    Equisetaceæ, 105. Calamites, 107. Filicites or Fossil Ferns, 109.
    Pachypteris, 112. Sphenopteris, 112. Cyclopteris, 114. Neuropteris,
    115. Glossopteris, 115. Odontopteris, 116. Anomopteris, 116.
    Tœniopteris, 117. Pecopteris, 118. Lonchopteris, 119. Phlebopteris,
    120. Clathropteris, 121. Stems of Arborescent Ferns, 122.
    Caulopteris, 123. Psarolites, 123. Sigillariæ and Stigmariæ, 125.
    Internal Structure of Sigillariæ, 130. Stigmaria, 132. Lepidodendron,
    137. Lepidostrobus, 140. Triplosporite, 142. Lycopodites, 143. Halonia
    and Knorria, 143. Asterophyllites, 145. Sphenophyllum, 147.
    Cardiocarpon, 147. Trigonocarpum, 148. Fossil Cycadaceæ, 150.
    Pterophyllum, 152. Zamites, 152. Trunks and Stems of Cycadaceæ, 156.
    Mantellia, 157. Clathraria, 159. Endogenites, 163. Fossil Coniferæ,
    164. Fossil Coniferous Wood, 167. Palæoxylon, 167. Pence, 168.
    Araucarites, 168. Sternbergia, 168. Petrified Forests of
    Conifers, 169. Coniferous Wood in Oxford Clay, 172. Coniferous Wood
    in Chalk, 173. Tertiary Coniferous Wood, 175. Fossil Foliage and
    Fruit of Coniferæ, 175. Araucaria, 175. Pinites, 176. Walchia, 177.
    Abietites, 178. Thuites, 180. Voltzia, 180. Taxites, 181. Nœggerathia,
    181. Fossil Resins and Amber, 181. Fossil Palms, 183. Fossil
    Palm-leaves, 185. Fossil Fruits of Palms, 186. Fossil Fruits from the
    Isle of Sheppey, 186. Nipadites, 190. Fossil Fruit of Pandanus, 192.
    Wood perforated by Teredines, 193. Fossil Liliaceæ, 194. Fossil
    Fresh-water Plants, 195. Fossil Fruits of Chara, 195. Fossil
    Nymphaeæ, 197. Fossil Flowers, 197. Fossil Angiosperms, 197. Fossil
    Flora of Œningen, 200. Carpolithes, 202. Fossil Dicotyledonous Trees,
    203. Dicotyledons of the Cretaceous Epoch, 205. Retrospect of Fossil
    Botany, 206. On Collecting British Fossil Vegetables, 211. British
    localities of Fossil Vegetables, 213.

  PART III.--Fossil Zoology, 216.

  Chapter VII.--Fossil Zoophytes; Porifera or Amorphozoa; Polypifera
    or Corals; Bryozoa or Molluscan Zoophytes, 218. Fossil Porifera,
    219. On the Sponges in Chalk and Flint, 222. Spongites, 223.
    Fossil Zoophytes of Faringdon, 226. Scyphia, 227. Cnemidium, 228.
    Chenendopora, 228. Tragos, 229. Siphonia, 230. Choanites, 233.
    Paramoudra, 236. Clionites, 238. Spicula of Sponges, 238.
    Spiniferites, 239. Ventriculites, 242. Polype in Flint, 250. Fossil
    Polypifera, 251. Graptolites, 255. Fungia, 256. Anthophyllum, 257.
    Turbinolia, 257. Caryophillia, 257. Favosites, 258. Catenipora, 259.
    Springopora, 259. Lithostrotion, 260. Cyathophyllum, 260. Astræa,
    262. Madrepora, 264. Millepora, 264. Lithodendron, 264. Gorgonia,
    265. Fossil Bryozoa, 265. Flustra, 266. Crisia, 269. Retepora,
    269. Fenestrella, 270. Petalæpora, 270. Pustulopora, 270.
    Homœsolen, 271. Idmonea, 271. Verticillipora, 273. Lunulites, 273.
    Geological Distribution of Fossil Zoophytes, 273. On Collecting
    Fossil Corals, 276. British localities, 278.

  Chapter VIII.--Fossil Stelleridæ; comprising the Crinoidea and
    the Asteriadæ, 280. Crinoidea, 281. Pentacrinus, 282. Fossil
    Crinoidea, 283. Fossil Stems of Crinoidea, 284. Pulley-stones,
    285. Apiocrinus, 288. Bourqueticrinus, 291. Encrinus, 292.
    Pentacrinites, 293. Actinocrinus, 295. Cyathocrinus, 295.
    Rhodocrinus, 297. Eugeniacrinus, 297. Pentremites, 297. Cystidea,
    298. Marsupites, 299. Fossil Asteriadæ, 301. Fossil Ossicula of
    Star-Fishes, 303. Ophiura, 304. Goniaster, 306. Asterias, 307.
    Geological Distribution of the Crinoidea, 308.

  Chapter IX.--Fossil Echinidæ, 311. Cidaritidæ, 314. Cidaris, 316.
    Diadema, 318. Echinus, 318. Salenia, 318. Spines of Cidarites,
    319. Flint Casts of Cidarites, 320. Cidaritidæ of the Palæozoic
    Rocks, 321. Clypeasteridæ, 322. Galerites, 322. Holectypus, 324.
    Discoidea, 324. Clypeideæ, 325. Clypeus, 325. Nucleolites, 326.
    Spatangidæ, 326. Ananchytes, 327. Micraster, 328. Toxaster, 329.
    Holaster, 330. Geological Distribution of Echinites, 330. On
    Collecting and Developing Echinodermata, 331.

  Chapter X.--Fossil Foraminifera; and Microscopical Examination of
    Chalk and Flint, 336. Foraminifera, 339. Classification of the
    Foraminifera, 342. Nummulites, 344. Orbitoides, 346. Siderolina,
    346. Fusulina, 346. Nodosaria, 347. Cristellaria, 348. Flabellina,
    348. Polystomella, 348. Lituola, 348. Spirolina, 349. Globigerina,
    350. Nonionina, 350. Rotalia, 351. Rosalina, 351. Textularia,
    352. Verneuilina, 352. Strata composed of Foraminifera, 352.
    Foraminifera of the Chalk and Flint, 355. Fossil Remains of the
    Soft Parts of Foraminifera, 357. Foraminifera-Limestones of
    India, 362. Foraminifera-deposit at Charing, 363. Foraminifera of
    the Oolite, Lias, &c. 364. Foraminifera-deposits of the United
    States, 364. Foraminifera of the Carboniferous Formations, 365.
    Foraminifera-Limestone of New Zealand, 366. Tertiary Foraminifera,
    366. Foraminifera of the Fens of Lincolnshire and Cambridgeshire,
    367. Recent Foraminifera-deposit at Brighton, 368. Geological
    Distribution of the Foraminifera, 369. Instructions for the
    Microscopical Examination of Chalk, Flint, and other Rocks, 371.

  Chapter XI.--Fossil Testaceous Mollusks, or Shells, 374. Mollusca,
    374. Acephala, 375. Encephala, 378. Fossil Bivalve Shells, 381.
    Shell-Rocks, 382. Fossil Brachiopoda, 388. Terebratula, 389.
    Spirifer, 390. Rhynchonella, 391. Pentamerus, 391. Orthis, Leptæna,
    and Productus, 392. Calceola, 392. Crania, 392. Orbicula, 392.
    Obolus, 392. Lingula, 393. Hippurites, 393. Fossil Shells of the
    Lamellibranchiates, 394. Monomyaria, 395. Ostrea, 395. Gryphæa,
    396. Spondylus, 398. Plagiostoma, 399. Plicatula, 400. Pecten, 400.
    Inoceramus, 401. Avicula, 404. Dimyaria, 404. Venericardia, 405.
    Pectunculus, 405. Nucula, 406. Pinna, 406. Mytilus, 407. Modiola,
    407. Pholadomya, 408. Pholas, 408. Teredo, 410. Trigonia, 412.
    Fossil Fresh-water Bivalves, 413. Unio, 414. Cyclas, 416. Fossil
    Pteropoda, 417. Fossil Gasteropoda, 417. Fresh-water Univalves,
    421. Paludina, 421. Limnæus, 423. Planorbis, 423. Melanopsis, 424.
    Marine Univalves, 424. Fusus, 425. Pleurotoma, 425. Cerithium,
    425. Potamides, 425. Rostellaria, 426. Dolium, 426. Trochus,426.
    Solarium, 426. Conus, 426. Pleurotomaria, 427. Euomphalus, 429.
    Murchisonia, 430. Sphærulites, 430. Molluskite, 432. Geological
    Distribution of Bivalve and Univalve Mollusks, 436. On the
    Collecting and Arranging Fossil Shells, 441. British Localities of
    Fossil Shells, 443.

                         CONTENTS OF VOL. II.

                Description of Frontispiece (Plate II.)

                    List of Lignographs in Vol. II.

                          Table of Contents.

                        PART III.--_continued_.

  Chapter XII.--Fossil Cephalopoda, 447.

  Chapter XIII.--Fossil Articulata, 503.

  Chapter XIV.--Fossil Ichthyology; Sharks, Rays, and other Placoid
    Fishes, 562.

  Chapter XV.--Fossil Ichthyology; Ganoid, Ctenoid, and Cycloid Fishes,
    600.

  Chapter XVI.--Fossil Reptiles; Enaliosaurians and Crocodiles, 643.

  Chapter XVII.--Fossil Reptiles; Dinosaurians, Lacertians,
    Pterodactyles, Turtles, Serpents, and Batrachians, 684.

  Chapter XVIII.--Fossil Birds, 759.

  Chapter XIX.--Fossil Mammals, 775.

  PART IV.--Geological Excursions, 827.

  Miscellaneous, 905.

  General Index, 909.

DIRECTIONS TO THE BINDER.

    Plate I.--Frontispiece to Vol. I.

    Plate II. Frontispiece to Vol. II.

    Plates III., IV., V., and VI., to follow the Table of Contents, and be
      placed opposite the description of each.

    Lign. 247, to face page 770.

                              DESCRIPTION

                                OF THE

                        FRONTISPIECE OF VOL. I.

PLATE I.

  Fig. 1.--A Fern in Coal-shale, from Leicestershire.

       2.--A Crustacean in Limestone, from Solenhofen.

       3.--A Fish (_Pycnodus rhombus_) in Limestone; from near
               Castel-a-mare.

       4.--Half the Lower Jaw of a Hyena, from a fissure in a
               sandstone rock, near Maidstone.

       5.--An Ammonite, from the Isle of Portland.

DESCRIPTION OF THE VIGNETTE OF VOL. I.

A Group of Fossils, containing

       Ammonites Mantellii, from the _Chalk-marl_, Sussex.
       Turrilites costatus, from the _Lower Chalk_, Rouen.
       Chondrites Bignoriensis, from the _Chalk-marl_, Sussex.
       Echinus and Fusus, from _Tertiary strata_, Palermo.

DESCRIPTION OF PLATE II.

_The Frontispiece of Vol. II._

A Fossil Fish of the Salmon tribe, allied to the Smelt; from the Chalk,
near Lewes, in Sussex.

[See Vol. II. pages 626 and 628.]

[Illustration: _Pl. 3._

_J. Dinkel del. G. Scharf lithog._

_Printed by Hullmandel & Walton_]

DESCRIPTION OF PLATE III.

_Incrustations, and Fossil Plants._

  Figs. 1, 2, 3.--Twigs of Larch and Hawthorn, coated with tufa, or
               travertine, from having been exposed to the dripping of
               an incrusting spring; from Russia; see p. 39.

         5.--A branch of recent _Chara_, with its fruit, with a thin
               pellicle of incrustation. Matlock.

         6, 7.--Hazel-nuts, from Belfast Lough: fig. 6 is lined with
               crystals of calcareous spar; fig. 7 is filled with a
               solid mass of the same mineral; see p. 71.

         4, 8.--Impressions of Dicotyledonous Leaves in Gypseous Marlstone,
               from Stradella, near Pavia; see p. 201.

         9.--Eocene Lacustrine or Fresh-water Limestone, from East Cliff
               Bay, Isle of Wight, with stems and seeds of Charge: slightly
               magnified; see p. 195.

        10.--Encrusted Twigs, from Matlock; the vegetable matter has
               perished, and left tubular cavities; see p. 39, and p. 873.

[Illustration: _Pl. 4._

_J. Dinkel del. G. Scharf lithog._

_Printed by Hullmandel & Walton_]

DESCRIPTION OF PLATE IV.

Various species of recent Diatomaceæ, to illustrate the Fossil remains
of this Tribe of Vegetables.

_For detailed descriptions, see pages 87-100._

  Figs. 1 to 5.--Various kinds of _Xanthidia_: figs. 2, 3, 4, found in a
               pond on Clapham Common, and fig. 1. living in a pond
               near Westpoint, United States.

         1.--Xanthidium _furcatum_: 1/24 of a line in diameter.

         2.-- --------- _hirsutum_: 1/36.

         3.-- --------- _aculeatum_: 1/24.

         4.-- --------- _fasciculatum_: 1/24.

         5.-- -------------------- variety of the above.

         2*.--Pyxidicula operculata; Carlsbad, Bohemia: 1/48 of a line in
               diameter.

         6.--Bacillaria vulgaris. 1/36 of a line in diameter. Pond on
               Clapham Common.

         7.--Cocconeis scutellum: from the Baltic: 1/24 of a line.

         8.--Navicula viridis: 1/6 of a line. Ponds on Clapham Common.

         9.--The same; a side view; showing the currents produced in the
               water by the animal when in locomotion.

        10.--Gallionella lineata: 1/36 of a line. Ponds on Clapham Common.

        11.--Gallionella moniliformis: 1/72 of a line.

        12.--Synhedra ulna: 1/9 of a line: the point _a_, marks the pedicle
               of attachment. Ponds on Clapham and Wandsworth Commons.

        13.--Podosphenia gracilis: 1/12 of a line; attached to a thread of
               _Calothria_ and having by self-division formed a
               radiating cluster. Common in the ditches communicating with
               the Thames in Battersea-fields.

        14.--Navicula splendida: 1/12 of a line in diameter.

        15.--Lateral view of the same.

        16.--Eunotia turgida: 1/14 of a line; the empty shell, with
               sixty-five ribs, viewed laterally.

        17.--A living group of the same: 1/20 of a line: a piece of
               _Conferva rivularis_, beset with these animalcules.
               The smaller species are _E. Westermanni_.

[All the above organisms were figured and described by Ehrenberg as
animals (_Polygastrica_), and are comprised in his family _Bacillaria_;
they are now, however, regarded as unquestionably vegetable structures,
belonging to the family of Algæ, termed _Diatomaceæ_.]

[Illustration: _Pl. 5._

_J. Dinkel del. G. Scharf lithog._

_Printed by Hullmandel & Walton_]

DESCRIPTION OF PLATE V.

_Illustrative of the Structure of Fossil Vegetables._

  Fig. 1.--Polished transverse section of silicified Monocotyledonous Wood,
             from Antigua; p. 185.

       1_a_.--Magnified 20 times linear.

       1_b_.--Magnified 75 times linear.

       2_a_.--Transverse section of silicified Coniferous Wood
             (_Abies Benstedi_) from the Kentish Rag, near Maidstone
             (Iguanodon quarry), × 120 linear; p. 173.

       2_b_.--Vertical or longitudinal section of the same, × 250
             linear.

       3_a_.--Transverse section of calcareous coniferous wood, from
             Willingdon, Sussex, × 80 linear; p. 173.

       3_b_.--Longitudinal section of the above, × 120 linear.

       4.--Slice of a transverse section of a recent Dicotyledonous Stem;
             showing, 1st, Pith or medullary column, occupying the centre;
             2d, Four bands of woody layers, separated by condensed lines
             of elongated tissue in series, and having large regular
             openings of vessels, with numerous medullary rays running
             continuously from the central pith to the bark; 3d, the bark.
             (_From Mr. Witham._)

       5.--Slice of a transverse section of a recent gymnospermous
             phanerogamic stem (of a Cycas), having a central pith, with
             woody layers separated by a condensed line, and consisting of
             elongated cellular tissue, arranged in a regular series;
             medullary rays and bark. (_From Mr. Witham._)

       6.--Bundles of vascular tissue in Stigmaria ficoides, × 12 linear.
             See p. 135.
           The two strands of vessels that appear as if on the surface (and
             are of a looser texture) are part of the vascular tissue of
             the stem, and become inflected (that is, bent over), and give
             rise to a band of vessels (the darker band seen between the
             above), that passes towards the bark or cortical covering.

       7.--Portion of a transverse section of one of the bundles of
             vascular tissue of _Sigillaria elegans_, × 20 linear.
             (From _M. Brongniart._) See p. 131.

           The convex portion on the left, and which in the original stem
             is situated towards the centre, is composed of the medullary
             vascular tissue formed of vessels irregularly disposed.

           The longitudinal bundles are the woody fibres arranged in a
             radiated circle: the smooth interspaces are medullary rays.

           The two distinct roundish spots of vascular tissue on the right
             of the ligneous zone occur irregularly on the outside of the
             woody circle, and are supposed to be detached bundles of the
             ligneous zone extending towards the leaves. See p. 131.

[Illustration: _Pl. 6._

_J. Dinkel del. G. Scharf lithog._

_Printed by Hullmandel & Walton_]

DESCRIPTION OF PLATE VI.

_Illustrative of the Structure of Fossil Teeth._

  Fig. 1_a_.--Tooth of _Psammodus porosus_, from the Mountain Limestone.
             See p. 587.

       1_b_.--Vertical section, a portion × 75 linear.

       1_c_.--Transverse section of the same, × 75.

       2_a_.--Tooth of _Ptychodus polygurus_, from the Chalk, near
             Lewes. See p. 585.

       2_b_.--Portion of longitudinal section, × 20.

       2_c_.--Portion of transverse section, × 20.

       3_b_.--Tooth of the _Labyrinthodon Jægeri_, from the New Red
             sandstone near Wirtemberg; half the natural size: the specimen
             presented by Dr. Jæger. See p. 742.

       3_a_.--A moiety of a transverse polished section, × 20.

       3_b_.--Portion of a vertical section near the apex, × 20.

       3_c_.--One of the anfractuosities of fig. 3_a_ × ×.

       4_a_.--Crown or upper portion of a tooth of a young _Iguanodon_,
             from Tilgate Forest. See p. 697.

       4_b_.--Portion of a vertical section of the above, × 20.

       4_c_.--A small portion of a transverse section of the same, × 20.

       5.--Tooth of _Goniopholis_, Tilgate Forest: half the natural size.
             See p. 678.

       6_a_.--Tooth of a reptile (probably of the _Hylæosaurus_), from
             Tilgate Forest; half the natural size. See p. 690.

       6_b_.--Portion of a vertical section of the same, × 20.

       7_a_.--Tooth of _Megalosaurus_, from Tilgate Forest. See p. 687.

       7_b_.--Portion of a vertical section of the same, × 10.

       8.--A small portion of a vertical section of a tooth of _Dendrodus_.
             See p. 618.

       9.--Portion of a transverse section of the base of a tooth of
             _Ichthyosaurus_, × 20. See p. 665.

      10_a_.--Tooth of _Lepidotus_, Tilgate Forest. See p. 606.

      10_b_.--The upper figure is a transverse section, and the lower
             a vertical section of the same, × 20.

                    LIST OF LIGNOGRAPHS IN VOL. I.

                             ============

                  (_Illustrative of Fossil Botany._)

    LIGN.                                                              PAGE

      1. Sections of Recent Vegetables                                   55
      2. Sections of Fern-Stems                                          62
      3. Nodule of Ironstone, enclosing a Fern Leaf                      69
      4. Siliceous Frustules of Diatomaceæ, and Spicules of Spongillæ    94
      5. Fossil Gallionellæ                                              96
      6. Organic Bodies in Porcelain Earth                               97
      7. Microphytes from the Tertiary deposits at Richmond, U.S.        98
      8. Confervites Woodwardii                                         101
      9. Chondrites Bignoriensis                                        102
     10. Delesserites (Fucoides) Lamourouxii                            103
     11. Moss and Conferva in transparent quartz                        104
     12. Equisetum Lyellii                                              105
     13. Equisetites columnaris                                         106
     14. Calamites decoratus                                            107
     15. Calamites in Coal-shale                                        108
     16. Pecopteris Sillimani                                           110
     17. Pachypteris lanceolata                                         112
     18. Sphenopteris elegans                                           112
     19. Sphenopteris nephrocarpa                                       113
     20. Sphenopteris Mantellii                                         113
     21. Cyclopteris trichomanoides                                     114
     22. Neuropteris acuminata                                          115
     23. Glossopteris Phillipsii                                        116
     24. Odontopteris Schlotheimii                                      116
     25. Anomopteris Mougeotii                                          117
     26. Tœniopteris latifolia                                          118
     27. Fig. 1, Pecopteris Murrayana                                   118
              2, Pecopteris lonchitica                                  118
     28. Lonchopteris Mantellii                                         119
     29. Fig. 1, Phlebopteris Phillipsii                                120
              2, Phlebopteris propinqua                                 120
     30. Clathropteris meniscoides                                      121
     31. Caulopteris macrodiscus                                        123
     32. Base of a Trunk of a Sigillaria, with root                     126
     33. Sigillariæ, in Coal Shale                                      128
     34. Sigillaria Saullii                                             129
     35. Silicified Stem of Sigillaria elegans                          130
     36. Stigmaria ficoides                                             133
     37. Transverse section of Stigmaria ficoides                       135
     38. Erect Stem of a Sigillaria, with Roots                         136
     39. A Terminal Branch of a Lepidodendron                           138
     40. Lepidostrobi, the Fruit of Lepidodendra                        141
     41. Stems of Halonia and Knorria, from the Coal Formation          144
     42. Asterophyllites equisetiformis                                 147
     43. Fig. 1, Sphenophyllum Schlotheimii                             148
              2, Sphenophyllum erosum                                   148
     44. Fossil Fruits, or Seed Vessels                                 149
     45. Foliage and upper part of the Stem of Cycas revoluta (recent)  150
     46. Part of a leaf of Pterophyllum comptum                         152
     47. Part of a leaf of Zamites pectinatus                           153
     48. Fruit of Zamites Mantellii                                     154
     49. Fossil Fruits of Cycadeous Plants                              156
     50. Mantellia nidiformis                                           157
     51. Mantellia cylindrica                                           158
     52. Clathraria Lyellii, inner Axis of the Stem of                  159
     53. Clathraria Lyellii, Stem of                                    160
     54. Clathraria Lyellii, part of Stem of                            161
     55. Clathraria Lyellii, Petiole of                                 161
     56. Clathraria Lyellii, summit of Stem, with petioles              162
     57. Clathraria Lyellii, water-worn Stem of                         163
     58. Fragment of Coniferous Wood in Flint                           174
     59. Fig. 1, Part of a Branch of Araucaria peregrina                176
              2, Calamites nodosus, with foliage                        176
     60. Walchia hypnoides                                              178
     61. Abietites Dunkeri                                              179
     62. Thuites Kurrianus                                              180
     63. Nipadites and other Fossil Fruits from the Isle of Sheppey     188
     64. Fossil Fruits from the Isle of Sheppey                         189
     65. Fossil Wood perforated by Teredines                            193
     66. Fossil Fresh-water Plants                                      196
     67. Fossil Fruits and Flower                                       198
     68. Imprints of Dicotyledonous leaves in Gypseous Marlstone        201

                  (_lllustrative of Fossil Zoology._)

     69. Coral and Spongites                                            224
     70. Fossil Zoophytes                                               227
     71. Fossil Sponge                                                  228
     72. Fossil Zoophytes                                               229
     73. Siphoniæ from the Greensand                                    231
     74. Polypothecia dichotoma                                         232
     75. Choanites Königi                                               234
     76. Paramoudra in the Chalk                                        237
     77. A group of Spiniferites in Flint                               239
     78. Spiniferites Reginaldi                                         241
     79. Spiniferites palmatus                                          241
     80. Flints, the forms of which are derived from Zoophytes          243
     81. Ventriculites radiatus                                         244
     82. Portions of Ventriculites                                      245
     83. Ventriculites alcyonoides                                      248
     84. A Coral Polype, in flint                                       250
     85. Graptolites in Wenlock Limestone                               255
     86. Favosites polymorpha                                           258
     87. Corals from the Dudley Limestone                               261
     88. Fossil Corals                                                  262
     89. Corals from the Chalk and Mountain Limestone                   268
     90. Stems of Encrinites and Pentacrinites                          284
     91. Recent Comatula and Fossil Crinoidea                           286
     92. Fossil Crinoidea                                               289
     93. Apiocrinites                                                   291
     94. Actinocrinites and Pentacrinite                                294
     95. Cyathocrinites planus                                          296
     96. Marsupites Milleri                                             300
     97. Fossil remains of Star-fishes                                  305
     98. Goniaster Mantelli                                             306
     99. Asterias prisca                                                308
    100. Fossil Turban Echinus with its Spines                          311
    101. Cidarites from the Oolite and Chalk                            316
    102. Fossil Spines of Cidarites                                     319
    103. Echinital remains in flint                                     320
    104. Echinites from the Chalk                                       323
    105. Holectypus inflatus                                            324
    106. Discoidea castanea                                             325
    107. Micraster cor-anguinum                                         328
    108. Toxaster complanatus                                           329
    109. Foraminifera from the Chalk                                    342
    110. Nummulites, or Nummulina                                       344
    111. Foraminifera from the Chalk                                    347
    112. Spirolinites in flint                                          349
    113. Nonionina Germanica (recent)                                   350
    114. Foraminifera in Chalk and flint                                351
    115. Chalk-dust, chiefly composed of Foraminifera                   355
    116. Section of a Rotalia in flint                                  356
    117. Rotalia in flint, with the fossilized body of the animal in
           the shell                                                    358
    118. Soft Bodies of Foraminifera extracted from the Chalk           359
    119. Remains of Foraminifera in chalk and flint                     361
    120. Fossil Oyster, from the Chalk                                  374
    121. Recent Bivalve Mollusc, showing the several parts of the
           shell and the animal                                         377
    122. Turritellæ from Bracklesham                                    383
    123. Shell-Conglomerate                                             385
    124. Shell-Limestone, from the mouth of the Thames                  386
    125. Terebratula and Rhynchonella                                   388
    126. Terebratula and Spirifer                                       390
    127. Shells and Echinite from the Oolite and Lias                   397
    128. Spondylus spinosus in Chalk-flint                              399
    129. Inoceramus Cuvieri of the Chalk                                401
    130. Flint with fragments of Inoceramus perforated by Clionites     403
    131. Unio Valdensis                                                 415
    132. Cyclas and Melanopsis                                          416
    133. Fossil Shells of Gasteropoda                                   418
    134. Polished Slab of Purbeck Marble                                422
    135. Univalves from the Chalk of Touraine                           427
    136. Univalves from the Mountain Limestone                          428
    137. Murchisonia bilineata                                          430
    138. Sphærulites from the Chalk                                     431
    139. Coprolites and Molluskite                                      432

                                  THE

                          MEDALS OF CREATION.

                              ⎼⎼⎼⎼⎼◆⎼⎼⎼⎼⎼

                             INTRODUCTION.

"Geology, in the magnitude and sublimity of the objects of which it
treats, ranks next to Astronomy in the scale of the Sciences."--_Sir J.
F. W. Herschel._

Geology, a term signifying a discourse on the Earth, (from two Greek
words: viz. γἡ, _ge_, the earth; and λὁγος, _logos_, a discourse,) is
the science which treats of the physical structure of the planet on
which we live, and of the nature and causes of the successive changes
which have taken place in the organic and inorganic kingdoms, from
the remotest period to the present time, and is therefore intimately
connected with every department of natural philosophy.

While in common with other scientific pursuits it yields the noblest
and purest pleasures of which the human mind is susceptible, it has
peculiar claims on our attention, since it offers inexhaustible and
varied fields of intellectual research, and its cultivation, beyond
that of any other science, is in a great measure independent of
external circumstances; for it can be followed in whatever condition
of life we maybe placed, and wherever our fortunes may lead us.

The eulogium passed by a distinguished living philosopher on scientific
knowledge in general, is strikingly applicable to geological
investigations. "The highest worldly-prosperity, so far from being
incompatible with them, supplies additional advantages for their
pursuit; they may be alike enjoyed in the intervals of the most
active business, while the calm and dispassionate interest with which
they fill the mind, renders them a most delightful retreat from the
agitations and dissensions of the world, and from the conflict of
passions, prejudices, and interests, in which the man of business finds
himself continually involved."[2]

[2] Sir J. F. W. Herschel, "Discourse on the Study of Natural
Philosophy."

From the present advanced state of geological science, particularly
of that department which it is the more especial object of these
volumes to elucidate, namely Palæontology,[3] or the study of Organic
Remains,--it seems scarcely credible, that but little more than a
century ago it was a matter of serious question with naturalists,
whether the petrified shells imbedded in the rocks and strata were
indeed shells that had been secreted by molluscous animals; or whether
these bodies, together with the teeth, bones, leaves, wood, &c. found
in a fossil state, were not formed by what was then termed the plastic
power of the earth; in like manner as minerals, metals, and crystals.

[3] Palæontology: from παλαιος, _palaios_, ancient--οντα, _onta_,
beings--λὁγος, _logos_, a discourse.

In a "Natural History of England," published towards the end of the
last century, it is gravely observed that at Bethersden in Kent, a
kind of stone is found full of shells, "_which is a proof that shells
and the animals we find in them living, have no necessary connexion_."
Another amusing instance of the ignorance on such subjects which
prevailed at no remote period, occurs in a "History of the County
of Surrey," in which it is stated that in a search for coal near
Guildford the borers broke, and "this was thought by Mr. Peter Lely,
the Astrologer, to have been the work of subterranean spirits, who
wrenched off the augers of the miners, lest their secret haunts should
be invaded."

But in the latter part of the seventeenth century, there were several
eminent men in England who were greatly in advance of the age in
which they lived, and strenuously exerted themselves to discover and
promulgate the true principles of Geology. Among these, Dr. Martin
Lister, physician to Queen Anne, was one of the most distinguished.
This accomplished naturalist, in his great work on shells, which
remains to this day a splendid monument of his labours, and of the
talents and filial affection of his two daughters, by whom all the
plates were engraved, figures and describes many fossil shells as real
animal productions, and carefully compares them with recent species.
He also recognised the distinction of strata by the organic remains
they contain; and to him the honour is due of having first suggested
the construction of geological maps;[4] he was likewise well acquainted
with the position and extent of the Chalk and other strata of the South
of England.[5]

[4] See Notes on the Progress of Geology in England, by W. H. Fitton,
M.D. &c. _Philos. Mag._ vols. i. and ii. for 1832 and 1833.

[5] This celebrated physician and British geologist died in 1712, and
was interred in the old church at Clapham; where a tablet to his memory
is affixed to the outside of the north wall of St. Paul's Chapel.

From the foreign writers, who at an early period had obtained some
correct notions of the structure of our planet, and of the nature of
the revolutions it had undergone, I select the following beautiful
and philosophical illustration of the physical mutations to which the
surface of the earth is perpetually subjected. It is from an Arabic
manuscript of the thirteenth century;[6] the narrative is supposed to
be related by Rhidhz, an allegorical personage.

[6] Quoted by Sir C. Lyell in his "Principles of Geology."

 "I passed one day by a very ancient and populous city, and I asked
 one of its inhabitants how long it had been founded? 'It is, indeed,
 a mighty city,' replied he; 'we know not how long it has existed,
 and our ancestors were on this subject as ignorant as ourselves.'
 Some centuries afterwards I passed by the same place, but I could
 not perceive the slightest vestige of the city; and I demanded of a
 peasant, who was gathering herbs upon its former site, how long it
 had been destroyed? 'In sooth, a strange question,' replied he, 'the
 ground here has never been different from what you now behold it.'
 'Was there not,' said I, 'of old a splendid city here?' 'Never,'
 answered he, 'so far as we know, and never did our fathers speak to us
 of any such.'

 "On revisiting the spot, after the lapse of other centuries, I
 found the sea in the same place, and on its shores were a party of
 fishermen, of whom I asked how long the land had been covered by the
 waters? 'Is this a question,' said they, 'for a man like you? this
 spot has always been what it is now.'

 "I again returned ages afterwards, and the sea had disappeared. I
 inquired of a man who stood alone upon the ground, how long ago the
 change had taken place, and he gave me the same answer that I had
 received before.

 "Lastly, on coming back again, after an equal lapse of time, I found
 there a flourishing city, more populous and more rich in buildings
 than the city I had seen the first time; and when I fain would have
 informed myself regarding its origin, the inhabitants answered me,
 'Its rise is lost in remote antiquity--we are ignorant how long it
 has existed, and our fathers were on this subject no wiser than
 ourselves.'"

We may smile at the ignorance of the inhabitants of the fabled cities,
but are we in a condition to give a more satisfactory reply should it
be inquired of us, "What are the physical changes which the country you
inhabit has undergone?"--and yet cautious observation, and patient and
unprejudiced investigation, are alone necessary to enable us to answer
the interrogation.

Dismissing from his mind all preconceived opinions, the student must
be prepared to learn that the earth's surface has been, and still is,
subject to perpetual mutation,--that the sea and land are continually
changing place,--that what is now dry land was once the bottom of the
deep, and that the bed of the present ocean will, in its turn, be
elevated above the water and become land,--that all the solid materials
of the globe have been in a softened, fluid, or gaseous state,--that
the relics of countless myriads of animals and plants are entombed in
the rocks and strata,--and that vast mountain-chains, and extensive
regions, are wholly composed of the petrified remains of beings that
lived and died in periods long antecedent to the creation of the human
race. Astounding as are these propositions, they rest upon evidence
so clear and incontrovertible, that they cannot fail to be admitted
by every intelligent and unprejudiced reader, who will bestow but a
moderate share of attention to the examination of the phenomena, of
which the following pages present a familiar exposition.

I cannot conclude these introductory observations, without adverting
to the incalculable benefits which result from scientific pursuits in
general, and of Geology in particular. An able modern writer has justly
remarked:--"It is fearfully true, that nine-tenths of the immorality
which pervades the better classes of society, originate from the want
of an interesting occupation to fill up the vacant time; and as the
study of the natural sciences is as attractive as it is beneficial, it
must necessarily exert a moral and even religious influence upon the
young and inquiring mind. The youth who is fond of scientific pursuits
will not enter into revelry, for frivolous or vicious excitements will
have no fascination for him. The overflowing cup, the unmeaning or
dishonest game, will not entice him. If any one doubts the beneficial
influence of these studies on the morals and character, I would ask him
to point out the immoral young man who is devotedly attached to any
branch of natural science: I never knew such an one. There may be such
individuals--for religion only can change the heart--but if there be,
they are very rare exceptions; and the loud clamours which are always
raised against the man of science who errs, prove how rarely the study
of the works of the Creator fails to exert an ennobling effect upon a
well-regulated mind. Fortunate, indeed, are the youth of either sex,
who early imbibe a taste for natural knowledge, and whose predilections
are not thwarted by injudicious friends."

And while Geology exerts this hallowing influence on the character, it
possesses the great advantage of presenting subjects adapted to every
capacity; on some of its investigations the highest intellectual powers
and the most profound acquirements in exact science are required; while
many of its problems may be solved by any one who has eyes and will use
them; and innumerable facts illustrative of the ancient condition of
our planet, and of its inhabitants, may be gathered by any diligent and
intelligent observer.

But it is surely unnecessary to dwell on the interest and importance
of a study, which instructs us that every pebble we tread upon bears
the impress of the Almighty's hand, and affords evidence of Creative
wisdom; that every grain of sand, every particle of dust scattered
by the wind, may be composed of the aggregated skeletons of beings,
so minute as to elude our unassisted vision, but which possessed an
organization as marvellous as our own;--a science whose discoveries
have realized the wildest imaginings of the poet,--whose realities
far surpass in grandeur and sublimity the most imposing fictions
of romance;--a science, whose empire is the earth, the ocean, the
atmosphere, the heavens;--whose speculations embrace all elements,
all space, all time;--objects the most minute, objects the most
colossal;--carrying its researches into the smallest atom which
the microscope can render accessible to our visual organs,--and
comprehending all the phenomena in the boundless Universe, which the
powers of the telescope can reveal.

And as no branch of natural philosophy can more strongly impress
the mind with that deep sense of humility and dependence, which
the contemplation of the works of the Eternal is calculated to
inspire, so none can more powerfully encourage our aspirations after
truth and wisdom. Every walk we take offers subjects for profound
meditation,--every pebble that attracts our notice, matter for serious
reflection; and contemplating the incessant dissolution and renovation
which are taking place around us in the organic and inorganic kingdoms
of nature, we are struck with the force and beauty of the exclamation
of the poet--

    My heart is awed within me, when I think
    Of the great miracle which still goes on
    In silence round me--the perpetual work
    Of Thy Creation, finished, yet renewed
    For ever!

PRELIMINARY REMARKS.

ON THE PLAN OF THE WORK, AND THE ARRANGEMENT AND SUBDIVISION OF THE
SUBJECTS IT EMBRACES.

With the view of economizing space, I would refer the reader to the
following volumes for figures and descriptions of such fossils as are
illustrated therein: by this arrangement I hope to afford the student a
comprehensive view of Palæontology, and yet restrict this work within
the limits which as a manual it would be inconvenient to exceed; at the
same time it will be complete in itself, and afford all the information
required by the amateur collector and general reader.

I. Dr. Buckland's _Bridgewater Treatise_: 2 vols. 8vo.--These volumes
contain numerous excellent figures of organic remains; and as the work
is, or ought to be, found in every good public or private library in
the kingdom, it will be accessible to most of my readers.

II. _The Wonders of Geology, or a Familiar Exposition of Geological
Phenomena_; _sixth_ edition, in two vols, with coloured plates, and
numerous figures; by the Author. Price 18_s._--This work is designed
to afford a general view of Geological phenomena, divested as much as
possible of scientific language: it is illustrated by numerous figures
of organic remains.

III. _Geological Excursions round the Isle of Wight and along the
adjacent Coasts of Hampshire and Dorsetshire._ One volume, richly
illustrated. By the Author. Price 12_s._

IV. _Petrifactions and their Teachings; or a Hand-book to the Gallery
of Organic Remains in the British Museum._ One vol. with many original
figures of the most interesting objects. By the Author.[7] Price 5_s._

[7] The three works above named consist of four volumes uniform with
the present edition of the "Medals of Creation:" this series of six
volumes comprises the popular geological works of the Author.

V. _A Pictorial Atlas of Fossil Remains;_ consisting of Coloured
Illustrations selected from "Parkinson's Organic Remains of a Former
World," and Artis' "Antediluvian Phytology." 1 vol. 4to. with
seventy-four coloured plates, and several lignographs, containing
nearly 900 figures of fossils. By the Author. Price 2_l._ 2_s._

To the above may be added Dana's _Mineralogy_, which treats of the
various mineral substances that enter into the composition of the rocks
and strata in which the fossil remains are imbedded.

A good geological map of Great Britain is indispensable. The small
map published by the Society for the Diffusion of Useful Knowledge,
edited by Sir R. Murchison, price 5_s._, is an excellent compendium;
but Mr. Knipe's large "_Geological Map of the British Isles_" is the
most complete and convenient for the traveller: price 3_l._ 3_s._ By
reference to the map, the geological structure, and the prevailing
fossils of a district, may be ascertained.

The above works are referred to as follows: viz.

  _Bd._ Dr. Buckland's Treatise.

  _Wond._ The Wonders of Geology.

  _Geol. I. of W._ Geology of the Isle of Wight.

  _Petrifactions._ Petrifactions and their Teachings.

  _Pict. Atlas._ Pictorial Atlas of Organic Remains.

The following works, to which reference will often be made, are thus
denoted:--

  _Foss. Flor._ The Fossil Flora of Great Britain, by Dr. Lindley, and
       W. Hutton, Esq. 3 vols. 8vo.

  _Vég. Foss._ Histoire des Végétans: Fossiles, par M. Adolphe
       Brongniart. 1 vol. 4 to.

  _Geol. Trans._ Transactions of the Geological Society of London. 5
       vols. 4to.; and New Series, in 5 vols.

  _Geol. Proc._ Geological Proceedings.

  _---- Journ._ ---------- Quarterly Journal.

  _Sil. Syst._ The Silurian System, by Sir R. I. Murchison. 2 vols.
       4to. with plates and map.

  _Org. Rem._ Parkinson's Organic Remains of a Former World. 3 vols.
       4to.

  _Oss. Foss._ Ossemens Fossiles, par Baron Cuvier. 5 vols. 4to.
       5^{me.} edit.

  _Min. Conch._ Sowerby's Mineral Conchology. 6 vols. 8vo.

  _Odont._ Odontography; a Treatise on the Comparative Anatomy of the
       Teeth, by Professor Owen. 2 vols. 8vo.

  _Brit. Mam._ British Fossil Mammalia; by the same Author. 1 vol. 8vo.

  _Brit. Rep._ Reports on British Fossil Reptiles in the British
       Association Transactions for 1839, and 1841; by the same Author.

  _Phil. York._ Geology of Yorkshire, by Professor John Phillips. 2
       vols. 4to.

  _South. D._ Fossils of the South Downs, 1 vol. 4to. 42 plates by the
       Author. 1822.

  _Geol. S. E._ Geology of the South-east of England. 1 vol. 8vo. by
       the same.

  _Tilg. For._ Fossils of Tilgate Forest. 1 vol. 4to. 20 plates; by the
       same. 1827.

  _Poiss. Foss._ Recherches sur les Poissons Fossiles, par M. Agassiz.
       4 vols. 4to, and 2 vols, folio.

  _Man. Geol._ Manual or Elements of Geology, by Sir C. Lyell. 1 vol.
       8vo. Edit. 1852.

The following abbreviations are also employed:--

§ 1. _Relative to the Rocks or Strata._

  _Drift._ Alluvial deposits, or Drift.

  _Tert._ Tertiary. _Lond. C._ London clay.

  _Cret._ Cretaceous formation. _U. Ch._ Upper chalk. _L. Ch._ Lower
       chalk.

  _Trias._ New Red Sandstone, or Triassic deposits.

  _Carb._ Carboniferous or Coal formation.

  _Mt. L._ Mountain or Carboniferous limestone.

  _Devon._ Devonian or Old Red Sandstone formation.

  _Sil. Syst._ Silurian System, or formation.

§ 2. _Relative to Organic Remains._

  _nat._ Natural size.

  × Magnified in diameter: _e.g._ × 8, magnified eight diameters, &c.

  × × Highly magnified; the degree not accurately determined.

  _inv._ Invisible to the naked eye.

  -- Less than natural: _e.g._ --2/3, reduced to two-thirds the
       diameter of the original.

  _Lign._ Lignograph or woodcut.

_Explanation of Terms._--Upon the occurrence of a scientific word
apparently requiring explanation, the _meaning_, where practicable,
is for the most part given in a parenthesis; for example, Caulopteris
(_fern-stem_); Phascotherium (_pouch-animal_); carboniferous
(_coal-bearing_); except in the case of arbitrary names, and of those
whose derivation cannot be concisely expressed.[8] With the view of
rendering these volumes more generally useful, English terminology
is in many instances made use of, though involving inelegance of
expression.

[8] Upwards of 300 scientific terms are explained in the Glossary,
"Wonders," vol. ii. p. 915-921.

The work is divided into four parts: the first is an _Introduction to
the Study of Organic Remains_; the second treats of _Fossil Botany_;
the third embraces _Fossil Zoology_; and the fourth, under the head
of _Geological Excursions_, illustrates the principles enunciated in
the course of the work, by practical observations on a few instructive
British localities.

PART I.

  1. On the British Strata and their Fossils.

  2. Arrangement and Characters of the British Formations.

  3. On the Nature of Fossils or Organic Remains.

  4. On Mineralized Vegetable Remains, and the mode of
       conducting their investigation.

  5. On Peat, Lignite, and Coal.

PART II.

FOSSIL BOTANY.

Classification of Fossil Vegetables.

  1. On the Fossil Remains of Cryptogamiæ.
  2.      "          "        Diatomaceæ.
  3.      "          "        Ferns.
  4.      "          "        Sigillariæ.
  5.      "          "        Lepidodendra.
  6.      "          "        Cycadaceæ.
  7.      "          "        Coniferæ.
  8.      "          "        Palms.
  9.      "          "        Angiosperms.

Retrospect.

British Localities of Fossil Plants.

PART III.

FOSSIL ZOOLOGY.

On the Fossil Remains of the Animal Kingdom.

   1. Zoophytes; Amorphozoa.
   2.     "      Polypifera.
   3. Echinoderms; comprising the
        a. Crinoidea, or Lily-shaped animals.
        b. Asteriada, or Star-Fishes.
        c. Echinida, or Sea-Urchins.
   4. Foraminifera.
   5. Shell-bearing Mollusca.
   6. Articulated animals; comprising
        a. Crustaceans.
        b. Insects.
   7. Fishes.
   8. Reptiles.
   9. Birds.
  10. Mammalia.
  11. Man.

Retrospect.

PART IV.

  I. Geological Excursions in various parts of England,
     illustrative of the method of observing geological
     phenomena, and of collecting Fossil Remains.

  II. Miscellaneous.
      On the prices of Fossils; lists of Dealers, &c.

  II. Appendix.

                                PART I.

                              ⎼⎼⎼⎼⎼◆⎼⎼⎼⎼⎼

                              CHAPTER I.

ON THE NATURE AND ARRANGEMENT OF THE BRITISH STRATA, AND THEIR FOSSILS.

"To discover order and intelligence in scenes of apparent wildness and
confusion is the pleasing task of the geological inquirer."--Dr. Paris.

The solid materials of which the earth is composed, from the surface to
the greatest depths within the reach of human observation, consist of
minerals and fossils.

Minerals are inorganic substances formed by natural operations, and are
the product of chemical or electro-chemical action.

Fossils are the durable remains of animals and vegetables which have
been imbedded in the strata by natural causes in remote periods, and
subsequently more or less altered in structure and composition by
mechanical and chemical agencies.

The soft and delicate parts of animal and vegetable organisms rapidly
decompose after death; but the firmer and denser structures, such as
the bones and teeth of the former, and the woody fibre of the latter,
possess considerable durability, and under certain conditions will
resist decay for many years, or even centuries; and when deeply
imbedded in the earth, protected from atmospheric influences, and
subjected to the conservative effects of various mineral solutions,
the most perishable tissues often resist decomposition, and becoming
transformed into stone, may endure for incalculable periods of time.
The calcareous and siliceous cases or frustules of numerous microscopic
plants are so indestructible, and occur in such inconceivable
quantities, that the belief of some eminent naturalists of the last
century, that every grain of flint and lime in certain rocks, may have
been elaborated by the energies of vitality, can no longer be regarded
as an extravagant hypothesis. Some idea may be formed of the large
proportion of the solid materials of the globe that has unquestionably
originated from this source, by a reference to the list of strata
which are wholly, or in great part, composed of animal and vegetable
structures, given in the "Wonders of Geology," p. 888.

There are also immense tracts of country that consist in a great
measure of the remains of plants in the state of anthracite, coal,
lignite, &c.; and districts covered with peat-bogs and subterranean
forests.

Although these relics of animal and vegetable organisms are found in
almost every sedimentary deposit, yet they occur far more abundantly,
and in a better state of preservation, in some strata than in others:
nor are they equally distributed throughout the same bed, but are
heaped together in particular localities, and occur but sparingly,
or are altogether absent, in other layers of the same rock. Neither
are the remains of the same kinds of animals and plants found
indiscriminately in strata of different ages: on the contrary, many
species are restricted to the most ancient, others to the most recent
formations; while some genera range through the entire series of
deposits, and also appear as denizens of the existing seas. Hence
organic remains acquire a high degree of importance, not only from
the intrinsic interest they possess as objects of natural history, but
also for the light they shed on the physical condition of our planet in
the remotest ages, and for the data they afford as to the successive
physical revolutions which the surface of the earth has undergone.

Fossils have been eloquently and appropriately termed Medals
of Creation; for as an accomplished numismatist, even when the
inscription of an ancient and unknown coin is illegible, can from the
half-obliterated effigy, and from the style of art, determine with
precision the people by whom, and the period when, it was struck;
in like manner the geologist can decipher these natural memorials,
interpret the hieroglyphics with which they are inscribed, and from
apparently the most insignificant relics, trace the history of beings
of whom no other records are extant, and ascertain the forms and habits
of unknown types of organization whose races were swept from the face
of the earth, ere the creation of man and the creatures which are his
contemporaries. Well might the illustrious Bergman exclaim, "_Sunt
instar nummorum memorialium, quæ de præteritis globi nostri fatis
testantur, ubi omnia silent monumenta historica_."

To derive from these Medals of Creation all the information they are
capable of affording, regard therefore must be had not only to their
peculiar characters, but also to the geological relations of the
strata in which they are imbedded. Data may be thus obtained by which
the relative age of a formation or group of strata can be determined,
as well as the mode of deposition, and the agency by which it was
effected; whether in the bed of an ocean, or of a lake, or estuary,--by
the action of the sea, or of rivers, or running streams,--by the
effects of icebergs or glaciers,--by slow processes through long
periods of time, or by sudden inundations or deluges,--or by the agency
of volcanoes and earthquakes.

The discovery that particular fossils are confined to certain deposits,
was soon productive of important results, which greatly tended to the
advancement of modern Geology; for although Dr. Lister, more than a
century before, had obtained a glimpse of this law, its principles
were neither understood nor regarded in this country until the late
Dr. William Smith, by his own unaided exertions, proved by numerous
observations on the British strata, its value and applicability for the
identification of a deposit, in districts remote from each other.

This phenomenon did not escape the notice of the distinguished French
philosophers, MM. Cuvier and Brongniart, who in their admirable work,
"_Géographie Minéralogique des Environs de Paris_," enunciated the same
principle:--

 "Le moyen que nous avons employé pour reconnoitre au milieu d'un si
 grand nombre de lits calcaires, un lit déjà, observé, dans un canton
 très-éloigné, est pris de la nature des fossiles renfermés dans chaque
 couche; ces fossiles sont toujours généralement les mêmes dans les
 couches correspondantes, et présentent d'un système de couche à un
 autre système, des différences d'espèces assez notables. C'est un
 signe de reconnoissance qui jusqu'à présent ne nous a pas trompés."[9]

[9] Géog. Min. Oss. Foss. tom. ii. p. 266.

Now, though recent discoveries have shown that this rule has many
exceptions, and that its too stringent adoption has been productive of
some erroneous generalizations, yet if employed with due caution it
is fraught with the most interesting results, and is the only certain
basis of our knowledge respecting the appearance, continuance, and
extinction, of the lost races of animals and plants, which were once
denizens of our planet.

[Sidenote: ROCKS AND STRATA.]

In the "Wonders of Geology" will be found a comprehensive sketch of
the composition and arrangement of the several formations or groups
of strata; and a reference to that work will afford the student the
necessary information on this branch of Geology. For the convenience
of the general reader I subjoin a synoptical view of the characters and
relations of the British fossiliferous deposits.

The total thickness of the entire series of rocks within the scope
of human examination, is estimated at from fifteen to twenty miles,
reckoning from the summits of the highest mountains to the greatest
depths hitherto penetrated; and as this vertical section scarcely
amounts to 1/400th of the diameter of the globe, it is familiarly
termed the Earth's crust. The substances of which the sedimentary
strata are composed have been deposited by the action of water, and
subsequently more or less modified in structure and composition by
heat, and by electro-chemical forces. The superficial accumulations of
water-worn detritus, consisting of gravel, boulders, sand, clay, &c.
are termed _Drift_, or _Alluvial_ deposits. When the successive layers
in which the sediments subsided are obvious, the deposits are said to
be _stratified_; when the nature of the materials has been altered by
igneous action or high temperature, but the lines of stratification
are not wholly effaced, the rocks are denominated _metamorphic_
(_transformed_). When all traces of organic remains and of sedimentary
deposition are lost, and the mass is crystalline, and composed of
known products of igneous action, such rocks are named _plutonic_, as
granite, sienite, trap, basalt, porphyry, and the like. Lastly, rocks
resembling the lavas, scoria, and other substances emitted by burning
mountains still in activity, are called _volcanic_.

The sedimentary origin ascribed to ancient crystalline rocks is, of
course, hypothetical, since all evidence of aqueous deposition is
wanting, and the minerals (_mica_, _quartz_, and _felspar_) of which
they are so largely constituted, are not readily soluble in water
under ordinary circumstances. But rocks unquestionably deposited by
water, when exposed to intense heat under great pressure, acquire
a crystalline structure (_Wond._ p. 864); and a series of changes,
from a loose earthy deposit, to compact volcanic lava, may be traced
in numerous instances, so as to leave but little doubt that the
rocks called primitive or primary, _may_ have originally been either
argillaceous, siliceous, or calcareous strata, abounding in organic
remains (_Wond._ p. 873). These crystalline masses have been formed
at successive periods; for granite is found of all ages, occurring
in the most ancient, as well as in comparatively modern epochs. The
difference between the composition and aspect of these rocks, and those
of recent volcanoes, is with much probability ascribed to the fact
that the latter are of sub-aerial origin; that is, were erupted on the
surface, and the gaseous products in consequence escaped; while the
former were ejected at great depths, either beneath the sea, or under
immense accumulations of other deposits, and being thus subjected to
great pressure, the volatile elements were confined, and formed new
combinations: in like manner as chalk when burnt in the open air is
converted into lime, the carbonic acid gas escaping; but when exposed
to the same degree of heat in a closed iron tube, is transformed into
granular marble (_Wond._ p. 104).

From these ancient crystalline rocks generally underlying the
sedimentary deposits, and never appearing as if they had been ejected
from a crater, the term _hypogene_[10] (_nether-formed_) is employed
by Sir C. Lyell to designate the whole class; and they are subdivided
into, 1. _plutonic_, those in which all traces of sedimentary origin
are lost, as granite; and 2. _metamorphic_, those which still manifest
traces of stratification, as mica-schist, &c.

[10] Nether-formed, from ιπο, _hypo_, under; and γἱνομαι, ginomai, to be
formed.

The fossiliferous rocks are, for the convenience of study, separated
into three grand divisions.

1. The Tertiary; comprising the deposits between the Chalk and the
superficial Drift and modern Alluvium.

2. The Secondary; from the _Chalk_ to the _Trias or New Red_, inclusive.

3. The Palæozoic; from the _Permian_ to the _Silurian_; including the
vast series of unfossiliferous slate rocks termed the _Cambrian_, in
which all traces of organic remains are lost.

In the following arrangement the strata are enumerated as if lying
in regular sequence, one beneath the other; but in nature such an
unbroken series has never been observed. A few groups only occur in
a serial order, and these but rarely in their original position. The
beds are for the most part disrupted, and lie in various angles of
inclination; sometimes they are completely retroverted, the newer
strata underlying those upon which they were originally deposited. The
order of succession has been ascertained by careful observation of
the relative superposition of the respective members of the series in
different countries; and from an immense number of facts collected by
able observers in every part of the globe.

This synopsis presents a chronological arrangement of the rocks
according to the present state of geological knowledge, but it must
not be supposed that these rigid distinctions, these hard lines, which
are necessary to facilitate the acquisition of a general idea of the
phenomena attempted to be explained, exist in nature. By whatever
names we designate geological periods, there appear to be no clearly
defined boundaries between them in reference to the whole earth:
such well marked lines may be seen in particular localities, but
daily experience teaches us that there is a blending, and a gradual
and insensible passage, from the lowest to the highest sedimentary
strata, particularly in respect of fossil remains. The terms employed
to designate formations can only be considered as expressing the
predominance of certain characters, to be used provisionally, as a
convenient mode of classifying and generalizing the facts collected,
whilst that knowledge is accumulating which in after times will reveal
the nature and order of succession of the principal events in the
earth's physical history.[11]

[11] "Wonders of Geology," p. 892.

Dr. Buckland's "Bridgewater Treatise" (Vol. II. _frontispiece_)
contains a comprehensive Diagram of the rocks and strata of which the
crust of the earth is composed; it was drawn by the late Mr. Thomas
Webster.

CHAPTER II.

SYNOPSIS OF THE BRITISH STRATA.

 "Hard lines are admissible in Science, whose object is not to imitate
 Nature, but to interpret her works."--Greenough.

The classification of the stratified rocks is based on three principal
characters; namely, 1, the mineral structure; 2, the order of
superposition; and 3, the nature of the organic remains; the following
synopsis has been drawn up in accordance with these principles.[12]

[12] See "Wonders of Geology," vol. i. pp. 200-207, for a Synoptical
Table of the principal rocks.

CHRONOLOGICAL ARRANGEMENT OF THE BRITISH FORMATIONS.

COMMENCING WITH THE UPPERMOST OR NEWEST DEPOSITS.

Modern or Human Epoch.

Alluvial Deposits: remains of Man and existing species of mammalia.

Post-Pliocene.

Drift; Boulder clay; Till; &c. comprising the superficial irregular
accumulations of transported materials, consisting of gravel, boulders,
sand, clay, &c.

 _Observations_.--These beds have been formed by a variety of causes;
 by land-floods and inundations, by irruptions of the sea, and by the
 agency of glaciers and icebergs. They are the catacombs of the extinct
 colossal mammalia--of the mastodon, mammoth, rhinoceros, hippopotamus,
 elk, horse, ox, whale, &c. They cannot be definitively separated from
 those of the Modern or Human epoch, for the gravel beds near Geneva,
 which closely resemble the newest tertiary drift in materials and
 position, abound in bones of animals, almost all of which belong to
 existing species.[13]

[13] See M. Pictet's "_Palæontologie_."

Tertiary Epochs.

An extensive series, comprising many isolated groups of marine
and lacustrine deposits, containing fossil remains of animals and
vegetables of all classes; the greater number of genera and species in
the most ancient or lowermost beds belong to extinct types.

_Subdivisions_:--

    1. The Pliocene[14] (_more new_, or _recent_.[15] _Wond._ p. 221);
       strata in which the shells are for the most part of recent
       species, having only about ten per cent of extinct forms.
       (_Norwich Crag._)

    2. The Miocene (_less recent_,[16] _Wond._ p. 221); containing about
       20 per cent of recent species of shells. (_Suffolk Crag._)

    3. The Eocene (_dawn of recent_,[17] in allusion to the first
       appearance of recent species--_Wond._ p. 226); the most ancient
       tertiary strata contain but very few existing species of shells;
       not more than five per cent. (_London, Hants, and Paris basins._)

[14] In the present state of our knowledge, this arrangement is of great
utility, but it will probably require considerable modification, and
must, perhaps, hereafter be abandoned; for it cannot be doubted, that
strata in which no recent species have yet been found, may yield them
to more accurate and extended observations, and those in which only a
few recent species are associated with a large number of extinct forms,
may have these proportions reversed.

[15] From πλειων, _pleion_, more; and καινος, _kainos_, recent.

[16] From μεἱων, _meion_, less, and recent.

[17] From ἠως, _eos_, the dawn or commencement, and _recent_.

 _Obs._--The marine are often associated with fresh-water deposits,
 and the general characters of the Tertiary system are alternations of
 marine and lacustrine strata. In England the most important Tertiary
 deposits are those of the London basin, the Isle of Sheppey, the
 south-western coasts of Sussex and Hampshire, the north of the Isle of
 Wight, and the eastern coasts of Essex, Norfolk, Suffolk. (_Wond._ p.
 226.)

Secondary Epochs.

The Cretaceous or Chalk Formation. (_Wond._ p. 296). A marine
formation, comprising a vast series of beds of limestone, sandstone,
marl, and clay, &c.; characterized by remains of extinct zoophytes,
mollusks, cephalopods, echinoderms, crustaceans, fishes, &c.;
lacertians, crocodilians, chelonians, and other extinct reptiles;
drifted coniferous and dicotyledonous wood and foliage, fuci, &c.

_Subdivisions_:--

  1. The _Maestricht beds_. Friable coralline and shelly limestones,
     with flints and chert.

  2. _Upper Chalk_, with flints      } _Craie blanche_ of the French
                                     }   geologists.
  3. _Lower Chalk_, without flints   }

  4. _Chalk-marl_                      _Craie tufeau._

  5. _Firestone_, Malm-rock, Upper   } _Glauconie crayeuse._
       Greensand, or Glauconite      }

  6. _Galt_, or Folkstone-marl         _Glauconie sableuse._

  7. _Shanklin_, or Lower Greensand. { _Formation néocomien_; which
                                     {   is divided into _N. supérieur_,
                                     {   the English upper divisions
                                     {   of the Greensand or Kentish
                                     {   rag; and _N. inférieur_, the
                                     {   lower beds of sand and clay,
                                     {   of the southern shore of the
                                     {   Isle of Wight, at Atherfield.[18]

[18] Another subdivision, with _other_ names (chiefly derived from
French localities), has lately been proposed by M. D'Orbigny; which I
notice with the more regret, since this eminent naturalist formerly
repudiated the censurable practice of many modern systematists,
of changing established names of strata and fossils, without any
just cause. The British geologist will smile to see the Wealden
Formation--so eminently distinguished in England and Germany by its
extent, thickness, and remarkable fauna and flora,--ranked as a
subordinate member of the "_Formation néocomien_," of France.

 _Obs._--The Maestricht beds are chiefly composed of fawn-coloured
 limestones of friable texture; containing peculiar species of corals,
 shells, fishes, reptiles, &c. The _Chalk_ is generally white, but
 in some localities is of a deep red, in others of a yellow colour;
 nodules, layers, and veins of flint occur in the upper, but are seldom
 present in the lower chalk. The _Marl_ is an argillaceous limestone,
 which generally prevails beneath the white chalk; it sometimes
 contains a large intermixture of green or chlorite sand, and then
 is called _Firestone_, or _Glauconite_. The _Galt_ is a stiff, blue
 or blackish clay, abounding in shells which frequently retain their
 pearly lustre. The _Greensand_ is a triple alternation of sands and
 sandstones with clays; and beds of cherty limestone called _Kentish
 Rag_.

The Wealden; a formation, whose fluviatile character was first
observed and established by the researches of the author (_Wond._
p. 360). A series of clays, sands, sandstones and limestones, with
layers of lignite, and extensive coal-fields; characterized by the
remains of several peculiar terrestrial reptiles, namely, _Iguanodon_,
_Hylæosaurus_, _Pelorosaurus_, _Megalosaurus_; _Crocodilians_ and
_Chelonians_; _Enaliosaurians_; _Pterodactyles_, &c.; Fishes of
fluviatile and marine genera; Insects of several orders; fresh-water
mollusks and crustaceans; conifers, cycads, ferns, &c.

_Subdivisions_:--

  1. _Weald-clay_, with Sussex or Petworth marbles.

  2. _Tilgate-grit_, and _Hastings sands_.

  3. _Ashburnham clays_, shales, and grey limestones.

  4. _Purbeck beds_; argillaceous and calcareous shales, and
       fresh-water limestones and marbles. Petrified forest, and layers
       of vegetable earth; with Cycads and Conifers.

 _Obs._--Clays and limestones, almost wholly composed of fresh-water
 snail-shells, and minute crustaceans, generally occupy the uppermost
 place in the series in Sussex; sands and sandstones, with shales, and
 lignite, prevail in the middle; while in the lowermost, argillaceous
 beds, with shelly marbles or limestones, again appear; and, buried
 beneath the whole, is a petrified pine-forest, with the trees still
 erect, and the vegetable mould undisturbed! The upper clay beds and
 marbles form the deep valleys or Wealds of Kent and Sussex, and the
 middle series constitutes the Forest-Ridge. The Purbeck strata are
 obscurely seen in some of the deepest valleys of eastern Sussex;
 they emerge on the Dorsetshire coast, form the Island or Peninsula
 whose name they bear, and surmount the northern brow of the Isle of
 Portland. On the southern coast of the Isle of Wight, the Wealden
 beds emerge from beneath the Greensand strata between Atherfield and
 Compton Bay on the western limit, and in Sandown Bay on the eastern;
 and their characteristic fossils are continually being washed up on
 the sea-shore.

The Jurassic or Oolitic Formation. (_Wond._ pp. 202, and 491). A
marine formation of great extent and thickness, consisting of strata
of limestone and clay, which abound in extinct species and genera of
marine shells, Corals, Insects, Fishes, and terrestrial and marine
Reptiles. Land plants of many peculiar types, and the remains of two
genera of Mammalia.

_Subdivisions_:--

  Upper Oolite of Portland, Wilts, Bucks, Berks, &c.

  1. _Portland Oolite._ Limestone of an oolitic structure, abounding
       in ammonites, trigoniæ, &c. and other marine exuviæ. Green and
       ferruginous sands--layers of chert.

  2. _Kimmeridge clay._ Blue clay, with septaria, and bands of sandy
       concretions--marine shells and other organic remains--_ostrea
       deltoidea_. Beds of lignite.

  Middle Oolite of Oxford, Bucks, Yorkshire, &c.

  1. _Coral oolite_, or Coral rag. Limestone composed of corals, with
       shells and echinites.

  2. _Oxford clay_; with septaria and numerous fossils. Beds of
       calcareous grit, called _Kelloway-rock_ swarming with organic
       remains.

  Lower Oolite of Gloucestershire, Oxfordshire, and Northamptonshire.

  1. _Cornbrash_--a coarse shelly limestone.

  2. _Forest marble_; concretions of fissile arenaceous
       limestone--coarse shelly oolite--sand, grit, and blue clay.

  3. _Great oolite_--calcareous oolitic limestone and freestone;
       reptiles, corals, &c., upper beds full of shells.

  _Stonesfield slate_;--terrestrial plants, insects, reptiles,
       _Mammalia_.

  4. _Fullers earth beds_;--marls and clays, with fuller's
       earth--sandy limestones and shells.

  5. _Inferior oolite_--coarse limestone--conglomerated masses
       of terebratulæ and other shells--ferruginous sand, and
       concretionary blocks of sandy limestone, and shells.

  Lower Oolite, of Brora in Scotland.

  1. _Shelly Limestones_--alternation of sandstones, shales, and
       ironstone; land-plants.

  2. _Ferruginous limestone_, with carbonized wood and shells.

  3. _Sandstone and shale; with two beds of coal._

  Lower Oolite of the Yorkshire coast.

  1. _Cornbrash_--a provincial term for a bluish grey rubbly
       limestone, with intervening layers of clay.

  2. _Sandstones and clays_, with land-plants, thin beds of coal and
       shale--calcareous sandstone and shelly limestone.

  3. _Sandstone_--often carbonaceous, with clays; coal-beds, and
       ironstone, with remains of vegetables.

  4. Limestone; ferruginous and concretionary sands.

 _Obs._--The difference observable between the lower beds of the Oolite
 in the midland counties, and those of Yorkshire and Scotland, is a
 fact of considerable interest. The fluvio-marine accumulations of
 vegetable matter in the state of coal, with the remains of land-plants
 at Scarborough and Brora, together with the presence of insects,
 fresh-water crustaceans, mammalia, and terrestrial plants, in the
 Stonesfield slate, attest the existence of neighbouring land, and the
 action of rivers and currents.

The Lias. (_Wond._ p. 521) A series of clays, shales, and limestones,
with marine shells, cephalopoda, crinoidea, and fishes in
great abundance; reptiles, (particularly of two extinct genera,
_Plesiosaurus_, and _Ichthyosaurus_,) in immense numbers. Drifted wood
and land plants: coniferæ, cycadesæ &c.

_Subdivisions_:--

  1. Upper Lias shale, full of saurian remains, belemnites,
       ammonites, &c. intercalated with the lowermost beds of the
       Oolite: nodules and beds of limestone.

  2. Lias marlstone; calcareous, sandy, and ferruginous strata, very
       rich in terebratulæ and other marine shells.

  3. Lower Lias clay and shale, abounding in _gryphea incurva_, and
       other marine shells; intercalations of sands and clays, with
       nodules of limestone.

  4. Lias rock; a series of laminated limestones, with clay partings.
       Bone-bed, with numerous remains of fishes.

 _Obs._--The Lias is the grand depository of those tribes of marine
 reptiles, the _Ichthyosauri_ and _Plesiosauri_, whose remarkable
 forms, structure, and state of preservation, have excited the
 attention even of the most incurious. The collection of these
 remains in the British Museum, principally formed by Mr. Hawkins, is
 unrivalled.[19]

[19] See "Petrifactions," p. 337-367.

The Trias; or New Red Sandstone Formation,[20] (_Wond._ p. 533).
This group of rocks consists of variegated marls, sandstones, and
conglomerates, frequently of a red colour, with marine shells,
crinoideans, fishes, and reptiles; marine and terrestrial plants. This
series contains extensive deposits of rock-salt, and brine-springs.

[20] Called by some geologists _Poikilitic_ (variegated) group.

This formation comprises the _Trias_, or triple group, _viz._ the
_Keuper_, _Muschelkalk_, and _Upper Bunter Sandstein_, of the German
geologists.

_Subdivisions_:--

  1. Variegated red, blue, and white marls, and shales, with gypsum
       and beds of rock-salt. (_Marnes irisées_ of the French.)

  2. Variegated red and white sandstones.

  3. Conglomerates formed of the detritus of the older rocks.

  4. Bed mottled sandstone, and marls. (_Grès bigarré_ of the French.)

 _Obs._--To this formation belong the principal deposits in
 Leicestershire and other midland counties of England. Fossils are
 not generally abundant, but some localities yield highly interesting
 remains. The shelly limestone of Germany, called Muschelkalk, which
 contains the _Lily Encrinite_, &c. does not occur in England. Remains
 of Conifers allied to the Yew and Araucaria, are found near Coventry;
 and peculiar reptiles (_Labyrinthodons_) near Warwick.

Palæozoic Epochs.

The Permian Formation. (_Wond._ p. 533). The separation of the strata
now termed _Permian_ from the _Triassic_, with which they were formerly
classed, was first proposed by Sir Roderick Murchison, and is based on
the fact that the fossils hitherto discovered are entirely distinct
from any that occur in the Trias and subsequent formations; it is,
therefore, inferred, that after the deposition of the so-called Permian
strata, a complete change took place in the faunas and floras of the
lands and seas, and the Trias is _at present_ regarded as the dawn of a
new system of organic beings.

The strata comprised in this group are variegated blue and red marls
and sandstones, like those of the Triassic; magnesian or dolomitic
limestones; and conglomerates more or less coloured with peroxide of
iron.

_Subdivisions_:--

  1. Red and white marls.

  2. Yellow magnesian limestones, and dolomitic conglomerates of
       Yorkshire and Durham.

  3. Marl-slate in thin layers, containing reptiles and fishes. The
       Keuper schiefer or copper-schist of Mansfeld.

  4. Marls and variegated sandstones, sands, and clays.

 _Obs._--This group includes the _Lower Bunter_, _Zechstein_, and
 _Rothliegendes_[21] of the German geologists. The _Permian_ comprises
 all the deposits that intervene between the Triassic above, and the
 Carboniferous below; and it is believed that this formation contains
 but one type of animal and vegetable life.

[21] Signifying _Red-dead-layer_; it is a German mining term denoting
that the copper of the upper bed has died out; this layer not being
metalliferous.

The Carboniferous, or Coal Formation. (_Wond._ pp. 660-748).
Sandstones, grits, shales, layers of ironstone, and clay, with immense
beds of coal; fresh-water limestones sparingly; marine limestones
abundantly.

_Subdivisions_:--

  1. _The Coal Measures._--Sandstones, shales, and grits, with
       numerous beds and seams of Coal; ironstone nodules. Land
       plants in profusion. Intercalations of bands of limestone with
       fresh-water bivalves and crustaceans in some districts; and with
       marine shells in others.

  2. _Millstone Grit._--Sandstones, shales, and quartzose
       conglomerates and grit, (_provincially_, Millstone-grit): with
       shales and thin seams of coal, and plants of the coal-measures
       in some localities. The conglomerates and grits have evidently
       resulted from the destruction of granitic rocks.

  3. _Carboniferous_, or _Mountain Limestone_.--A series, nearly
       1,000 feet in thickness, of limestones and flagstones, abounding
       in crinoideans, corals, and marine shells and crustaceans;
       with layers and nodules of chert. Ores of lead, zinc, copper,
       barytes; fluor spar, &c. Limestones, with innumerable shells
       of the genera Productus, Spirifer, Goniatites, Orthocera,
       Bellerophon, &c. Several varieties of black, bluish grey, and
       variegated marbles. Coal occurs in the mountain limestone of
       some parts of Russia.

 _Obs._--The strata comprised in the carboniferous (coal-hearing)
 system, consist of sandstones more or less felspathic, and of
 dark bituminous shales with innumerable ferns, and other vascular
 cryptogamiæ, and coniferæ, &c. The uppermost group is composed of
 numerous alternations of coal, clay, shale, ironstone, and sandstone;
 the middle, of sandstones, shales, clays, and quartzose conglomerates,
 generally of a dull red colour; and the lowermost, of crystalline
 limestones with occasional layers of chert, abounding in marine
 shells, corals, crinoidea, and other exuviæ. These lower limestones
 are the principal repositories of the lead ores of Derbyshire.

The Devonian or Old Red Formation. (_Wond._ pp. 204 and 751).
Conglomerates, quartzose grits, sandstones, marls, and limestones;
the prevailing colour is a dull red. Shells, corals, and ganoid
fishes, of a very peculiar type. Reptiles, (Telerpeton; _Batrachians?_
_Chelonians?_); the most ancient reptilian remains hitherto discovered.
_Ferns_, _Lepidodendrons_, and other trees of the carboniferous flora;
fluviatile plants with batrachian ova(?).

_Subdivisions_:--

  1. Sandstone, quartzose conglomerates, and shale, with but few
       fossils.

  2. Flagstones, marls, and concretionary limestones; provincially
       termed _corn-stones_; laminated reddish and greenish micaceous
       sandstones (_prov. tilestones_). Peculiar genera of fish;
       orthocerata, and many species of marine shells.

 _Obs._--The term Devonian, by which the series of strata comprehended
 in this formation is now generally distinguished by geologists, was
 first proposed by Sir R. Murchison, as being more precise than the
 name formerly applied to this group. In Scotland, where the formation
 is of vast extent, it was first characterized by its peculiar ganoid
 fishes (Pterichthys, Coccosteus, Cephalaspis), and will probably
 always there retain the original name of Old Red.[22] In Devonshire
 it is marked by the presence of shells of a character intermediate
 between those of the Silurian and Carboniferous systems.

 The sandstones are in various states of induration, and when slaty,
 are employed for roofing. The red colour predominates in the marls,
 and is derived from peroxide of iron. The formation of these rocks
 has manifestly resulted from the waste of ancient slate rocks, the
 detritus of which is cemented together into coarse conglomerates. In
 South Devonshire (at Torquay, Babbicombe, &c.), beautiful coralline
 marbles occur in this formation.

[22] See the charming volume of Mr. Hugh Miller, entitled "The Old Red
Sandstone, or New Walks in an Old Field."

The Silurian System. (_Wond._ p. 765). Marine limestones, sandstones,
shales, and calcareous flagstones, characterized by peculiar types
of corals, crinoideans, mollusks, and crustaceans, constitute this
important and extensive system of rocks; the _Grauwacké_, or Transition
series of the earlier geologists.

_Subdivisions_:--

UPPER SILURIAN.

  1. _Ludlow rocks_;--slightly micaceous grey-coloured sandstones.
       Blue and grey argillaceous limestones. Dark-coloured shales and
       flagstones, with concretions of earthy limestone, containing
       marine shells, Orthocerata, Spirifers, and Trilobites. _Fishes._

  2. _Wenlock_, or _Dudley limestone_;--sub-crystalline blue and grey
       limestone, abounding in Trilobites, Crinoidea, Polyparia,
       Spirifers, Orthocerata, &c.

  3. _Wenlock shale_;--dark grey argillaceous shale, with nodules of
       sandstone.

LOWER SILURIAN.

  1. _Caradoc sandstone_;--shelly limestones, and finely laminated,
       slightly micaceous, greenish sandstones. Corals, Shells,
       Trilobites.

  2. _Llandeilo flags and limestones._ Freestone, conglomerates,
       grits, and limestones. Dark-coloured flags. Beds of schist with
       abundance of Trilobites and shells. The lowermost beds are full
       of small bivalves, termed _Lingulæ._

 _Obs._--The _Silurian System_, (so named by Sir R. Murchison, from
 the _Silures_, the ancient Britons who inhabited those parts of our
 island in which the geological relations of these strata were first
 recognised by him,) occupies the border counties of England and
 Wales, and spreads over a vast area of both North and South Wales,
 intervening between the Carboniferous series and the Cambrian or
 ancient slate-rocks of that country.[23] The strata are entirely of
 marine origin, and many of the beds (as the well-known Dudley or
 Wenlock limestone) are composed of shells, corals, crinoideans, and
 remains of that remarkable family of crustaceans termed Trilobites,
 cemented together by carbonate of lime. A few remains of Fishes occur:
 Reptiles are unknown. No vegetable relics, excepting _Fuci_, have been
 found in Britain below the _Devonian_ or _Old Red formation_.[24]

[23] "The Silurian System, founded on Geological Researches in the
Border Counties of England and Wales." In two parts, royal 4to., with
map, sections, &c., by Sir R. I. Murchison, G.C. St.S. &c. In studying
the beautiful map which accompanies the work, it must be borne in
mind that ten years have elapsed since Sir R. Murchison abrogated
the boundary line that separates the Cambrian and Silurian rocks
in this chart, from the conviction that those deposits constitute
but one natural system (see _Wond._ p. 80.3). For an account of the
Silurian rocks of other countries, see "Geology of Russia," by the same
Author. A summary of the characters of the Silurian System, by Sir R.
Murchison, is given in _Geolog. Journal_, vol. viii. pp. 173-183.

[24] "The Silurian System" contains excellent figures of all the organic
remains known at the period of its publication.

The Cambrian Formation. This term is applied to a largely developed
series of unfossiliferous slate-rocks and conglomerates, many thousand
yards in thickness.

 _Obs._--Certain beds of dark-coloured schists containing a few
 corals, fuci, and shells, are referred to the uppermost part of this
 formation by some eminent geologists, but it is more consonant to the
 established system of classification to regard these fossiliferous
 beds as the lowermost of the Silurian rocks. The fineness of grain,
 general aspect, hardness, and texture of these strata, are well
 known, from the general employment of slate for economical purposes.
 These rocks extend over a great part of Cumberland, Westmoreland, and
 Lancashire, reaching to elevations of 3,000 feet, and giving rise to
 the grand scenery of the Lakes, and of North Wales.

Hypogene Rocks. (_Wond._ p. 806.)

_Non-fossiliferous._

Metamorphic (_transformed_) or stratified crystalline rocks.

_Subdivisions._--

  1. _Mica-schist System._ (_Wond._ p. 843.) Probably sedimentary
       rocks altered by high temperature. Mica-slate, Quartz-rock,
       Crystalline limestone, Hornblende schist, &c.

  2. _Gneiss System._ Layers of Gneiss, Sienite and Quartz-rock,
       alternating with Clay-slate, Mica-schist, &c.

Plutonic Rocks; unstratified crystalline masses.

_Granitic System._ (_Wond._ p. 844.) Granite--a rock composed of mica,
quartz, and felspar; Porphyry; Serpentine; Trap. These rocks occur in
amorphous or shapeless masses, and in dykes and veins.

 _Obs._--No fossils have been detected in these rocks: but the intense
 igneous action which the masses appear to have undergone, may have
 obliterated all evidence of animal and vegetable structures, should
 any have been present, as well as the lines of stratification. By
 the aid of the microscope, we may yet perhaps solve the mystery
 which shrouds the origin of these rocks, and the student may take
 up the investigation with the certainty of obtaining much valuable
 information, even should the search for organic structures prove
 abortive. It is not, however, improbable that the siliceous frustules
 of diatomaceæ may have escaped destruction, and remain to reward the
 researches of some skillful and patient observer.

Volcanic Rocks. (_Wond._ p. 815.)

The products of subterranean fire or heat, erupted from profound depths
through fissures in the Earth's crust, whether in ancient or modern
times.

_Subdivisions._--

  1. _Trap, Basalt, Toadstone, Volcanic-tuff_; the erupted materials
       of ancient extinct volcanoes.

  2. _Lavas, Scoriæ, Pumice, Ashes_; ejected by modern volcanoes.

 _Obs._--These igneous products are of all ages, and they traverse
 alike the hypogene rocks and the older and newer sedimentary deposits.
 Their characters, and the effects they have produced, are considered
 in the work to which reference is made.

By a reference to the geological map of England (_Wond._ pl. i.
vol. i.), it will be seen, that the several formations appear on
the surface in a somewhat chronological order, as we pass from the
eastern or south-eastern part of the Island to the west or north-west.
Thus the principal Tertiary deposits are situated in the eastern
and south-eastern parts; and proceeding towards the north-west, we
traverse successively the _Secondary_--the _Chalk_, _Oolite_, _Lias_
and _Trias_; then the _Palæozoic_--_Permian_, _Carboniferous_,
and _Devonian_; next the _Silurian_ and _Cambrian_; and at length
_metamorphic_ and _primary_ rocks appear. It is this distribution
of the strata of the respective formations that has determined
the characters of the physical geography of England. The Alpine or
mountainous districts, which extend north and south along the western
portion of England and Wales, from Cornwall to Cumberland, are formed
by the elevated masses of the Silurian, Cambrian, and Metamorphic
rocks. These are succeeded by a band of the Carboniferous and Triassic
deposits, with a few intrusions of metamorphic and plutonic rocks, that
stretches from the coast of Devonshire, through the midland counties,
by Leicestershire and Derbyshire, to Newcastle. On the south-east
of this tract, the Oolite and Cretaceous formations, chiefly made
up of argillaceous and calcareous strata, constitute a diversified
agricultural district, extending from the southern shores of Hants and
Dorset to the coast of Yorkshire. The Wealden occupies the country
lying between the Chalk Downs of Sussex, Hants, Surrey, and Kent. The
Tertiary deposits lie in basins or depressions of the upper cretaceous
rocks in the south-eastern and eastern maritime districts, and on an
extensive area of these beds stands the metropolis of England; lastly,
irregular accumulations of Drift, containing mammalian remains in some
localities, are spread over the surface of the ancient formations, and
form the immediate subsoil of the most fertile regions.

CHAPTER III.

ON THE NATURE OF FOSSILS, OR ORGANIC REMAINS.

Fossils; Petrifactions.--It is very generally the case, that persons
who are not conversant with the nature of organic remains, suppose
that all fossils are petrifactions; and unless a specimen has the
aspect and hardness of stone, they regard it as of modern origin, and
devoid of interest. Hence they are surprised to find among the choicest
treasures in the cabinet of the geologist, shells and corals as perfect
in form, as if recently collected from the sea-shore; bones as little
changed, as if they had been interred but for a short period; and
teeth possessing their sharp edges and enamel unimpaired. In my early
researches I fell into this error, and threw away many beautiful shells
that were associated with casts of ammonites in the marl at Hamsey,
supposing, from their perfect state, that they had been accidentally
imbedded, and were not genuine fossils. But the state of preservation,
and the degree of change which an organic body has undergone in the
mineral kingdom, have no necessary relation to its antiquity. The
shells in some of the ancient secondary strata are frequently as little
changed as those in modern tertiary deposits. I have collected from the
lowermost clays of the Wealden, fresh-water shells with traces of the
epidermis, and the ligament by which the valves were held together,
perfect; and bones of reptiles from the strata of Tilgate Forest, as
light and porous as those of the bears and hyenas, from the Caverns of
Germany. On the other hand, fossil remains from the newest tertiary
formations are often completely petrified, that is, permeated by, or
transmuted into, stone.

The words _fossil_ and _petrifaction_ are so commonly used as
synonymous terms, even by educated persons, that it is necessary to
define the sense in which they are employed in these volumes.

_Fossils_ are the durable parts of animal and vegetable structures
imbedded in rocks and strata by natural causes at a remote period; thus
wood in a state of lignite, bog-wood, and coal, or of siliceous or
calcareous stone, is _fossil wood_; and bones or shells, whether in an
earthy and decaying state, or permeated by calc-spar, flint, or iron,
and converted into a hard mineral substance, are alike _fossil bones_
or _shells_.

_Petrifactions_ are the remains of animals and vegetables in which
the original structure is converted into stone, or, in other words,
is _petrified_; such are the silicified stems of trees from Antigua,
and Germany, and the calcified bones and shells in the Oolitic and
Wealden limestones. Such petrifactions may be correctly termed fossil
plants, bones, or shells; but similar organic remains, though of equal
antiquity, which have not undergone such changes, are not petrifactions
in the proper meaning of that term.

The process by which petrifaction is effected is still involved in
obscurity; mineral solutions have permeated the original tissues,
and the organic molecules have been replaced by mineral molecules,
but how this transmutation is produced is not understood. Mr. Dana's
observations and Mr. Jeffery's experiments have, however, thrown much
light on the process of silicification.[25]

[25] See _Wond._ p. 100.

_Incrustations._--Another prevalent error is that of considering
Incrustations to be fossils or petrifactions; a mistake which is
sanctioned by the custom of calling waters that are charged with
calcareous earth (_lime_), and deposit it in considerable quantity,
petrifying springs; as those of Matlock, and other places in
Derbyshire. (_Wond._ p. 76.) But incrustations are not petrifactions;
stems and branches of trees, skulls, bones, shells, &c., are simply
invested with a calcareous coating or crust, which is generally porous
and friable, but often crystalline and compact. The inclosed bodies
are not permeated by the stony matter; if the mass be broken, or
the incrustation removed, we find the twig, or stem, either dry and
shrivelled, as in the specimens, figs. 2, 3, 4, Plate III.; or tubular
cavities are left by the decay and removal of the vegetable structure,
as in fig. 10, Plate III.

But although incrustations be not petrifactions, natural specimens,
(not the so-called petrified nests and twigs, in which the bad taste of
the guardians of the Derbyshire springs is embodied, and dispersed all
over England,) are objects of considerable interest, as illustrative
of a process, by which important changes are effected in the mineral
kingdom. Thus springs as clear and sparkling as poet ever feigned or
sung, may transform beds of loose sand and gravel into rock, and porous
stone into solid marble, and cover extensive tracts of country with
layers of concretionary and crystalline limestone. This process is
effected in the following manner. Most fresh water holds in solution a
certain proportion of carbonate of lime; and changes of temperature, as
well as other causes, will occasion this calcareous earth to be in part
or wholly precipitated. The _fur_, as it is called, that lines a kettle
or boiler which has been long in use, affords a familiar illustration
of this fact. At the temperature of 60° lime is soluble in 700 times
its weight of water; and if to the solution a small portion of carbonic
acid be added, a carbonate of lime is formed, which is thrown down
in an insoluble state. But if the carbonic acid be in such quantity
as to supersaturate the lime, it is again rendered soluble in water:
it is thus that carbonate of lime, held in solution by an excess of
carbonic acid, not in actual combination with the lime, but contained
in the water, and acting as a menstruum, is commonly found in all
waters. An absorption of carbonic acid, or a loss of that portion which
exists in excess, will therefore occasion the lime to be set free, and
precipitated on the foreign bodies in the water, as stones, twigs,
leaves, &c.

The substance thus deposited is termed _tufa_, or travertine;[26] and
in some parts of Italy, and of our own Island, it constitutes beds of
stone of great extent, in which bones, shells, and the impressions of
leaves and stems, are preserved. The stalactites and stalagmites of
caverns have a similar origin; many of these caves are of incalculable
antiquity, and beneath their stalagmitic floors, the bones and teeth of
extinct carnivorous animals are found in vast quantities.

[26] _Travertine_, so called from the river _Tibur_, whose waters are
loaded with calcareous earth--_Tiburtina_, Ital. _travertina_.

Silicification, or petrifaction by Silex or Flint.--Silex, or the earth
of flint, is held in solution in large proportions, in certain thermal
or boiling springs, which, on cooling, deposit the siliceous matter
(in the same manner as the travertine is precipitated from incrusting
streams) on foreign substances, and produce exquisite chalcedonic
infiltrations of mosses, &c. But this operation is now only known to
be in activity in the immediate neighbourhood of foci of volcanic
action, as in the celebrated Geysers of Iceland (_Wond._ p. 95), and
the boiling springs of the volcano of Tongariro, in New Zealand (98).
We have everywhere evidence that in former periods, the petrifaction,
as well as the incrustation of organic bodies by silex, was carried on
to an immense extent; and, doubtless, far beneath the surface, the same
operation is at the present moment in constant progress, and effecting
as important changes in the consolidation of loose materials, as in the
earlier geological epochs.

The various states in which silex occurs have depended on its fluidity;
in quartz crystals the solution appears to have been complete; in agate
and chalcedony it was in a gelatinous state, assuming a spheroidal or
orbicular disposition, according to the motion given to its particles.
Its condition appears also to have been modified by the influence
of organic matter. In some polished slices of siliceous nodules the
transition from flint to agate, chalcedony, and crystallized quartz, is
beautifully shown. The curious fact, that the cavities of echinites in
chalk are almost invariably filled with flint, while their crustaceous
cases are changed into calc-spar, is probably, in many instances, to
be attributed to the animal matter having undergone silicification;
for the soft gelatinous parts are those which appear to have been most
susceptible of this transmutation. In some specimens, the oyster is
changed into flint, while the shell is converted into crystallized
carbonate of lime. In a Trigonia from Tisbury, formerly in the cabinet
of the late Miss Benett, of Norton House, near Warminster, the body
of the mollusk was completely metamorphosed into a pure chalcedony,
the branchiæ or gills being as clearly defined as when the animal was
recent. In specimens of wood from Australia (presented to the British
Museum by Sir Thomas Mitchell), which are thoroughly permeated by
silex, there are on the external surface some spots of chalcedony that
have apparently originated from the exudation of the liquid silex from
the interior in viscid globules filled with air, which burst, and then
collapsed, and became solidified in their present form.

In silicified wood the permeation of the vegetable tissues by the
mineral matter, appears to have been effected by solutions of silex of
a high temperature. In some examples the mineralization is simply a
replacement: the original substance has been removed atom by atom, and
the silex substituted in its place.

One of the most eminent naturalists and chemists of the United States,
Mr. Dana,[27] suggests that the reason why silica is so common a
material in the constitution of fossil wood and shells, as well as in
pseudo-morphic crystals,[28] is the ready solution of silex in water
at a high temperature (a fact affirmed by Bergman[29]) under great
pressure, whenever an alkali is present, as is seen at the present
time in many volcanic regions, and its deposition again when the water
cools. A mere heated aqueous solution of silica, under high pressure,
is sufficient to explain the phenomenon of the silicification of
organic structures. Mr. Dana states that a crystal of calc-spar in
such a fluid being exposed to solution, from the action of the heated
water alone, the silica deposits itself gradually on a reduction
of temperature, and takes the place of the lime, atom by atom, as
soon as set free. Every silicified fossil is an example of this
pseudo-morphism; but there seems to be no union of the silica with the
lime, for silicate of lime is of rare occurrence.[30]

[27] American Journal of Science for January 1845.

[28] Pseudo-morphic crystals are crystals moulded in the cavities
left by other crystals which they have replaced. See Dr. Blum on
Pseudo-morphous minerals.

[29] Bergman first determined the solubility of silex in simple water,
aided by heat, and demonstrated its existence in the Geysers and other
boiling springs of Iceland.--_Parkinson, Org. Rem._ vol. i. p. 324.

[30] See my "Notes on a Microscopical Examination of Chalk and Flint,"
Annals of Natural History, August 1845.

I proceed to consider the various states in which the remains of
animals and plants are preserved in the mineral kingdom, and shall
occasionally offer suggestions for collecting and preparing specimens;
but particular instructions on this head will be given in the sequel,
when the different kinds of fossils are respectively considered.

[Sidenote: FOSSIL ANIMAL REMAINS.]

Animal Remains.--Of the higher orders of animals, the more durable
portions of the skeleton, as the bones and teeth, are almost the
only parts that occur in a fossil state; except in some remarkable
instances, in which entire carcasses of extinct species of Elephant,
and of Rhinoceros, have been found imbedded in solid ice, and frozen
gravel. (_Wond._ p. 152.) The countries of arctic regions are now the
only localities in which such phenomena are likely to be met with;
it appears, however, that in some remote period, the bodies of large
mammalia were transported by icebergs into temperate regions, where
the ice melted, and the animals either sunk to the bottom of the sea,
or were drifted into estuaries, or stranded on the shore: the soft
parts then decomposed, and the skeletons and detached bones were left
imbedded in the silt, sand, or shingle.

In this manner alone can be explained the occurrence of bones and teeth
of the mammoth, rhinoceros, hippopotamus, &c. so common in the alluvial
or drifted deposits of this country; for these relics, though extremely
friable, and buried in shingle, boulders, and other transported
materials, are not water-worn, but in numerous instances remain as
sharp and perfect as when recent. In the ancient shingle of Brighton
cliffs (_Wond._ p. 114), I have found bones and teeth of horse, deer,
ox, whale, &c. impacted with quartz and granite pebbles and boulders;
the bones, though crumbling to pieces if not very carefully removed,
being entire, and the whole mass held together by calcareous spar,
deposited by water that had, during the lapse of ages, percolated
through the chalk-rubble above.

Fossil bones are found in four different states: 1. With their animal
matter, as in the bones of the Mastodons from Big-bone Lick, Kentucky.
2. With the animal matter removed. 3. With the earthy matter partly
removed, 4. With the animal matter carbonized, or converted into
bitumen; this change is common in the blue Lias clay; the bones retain
their usual quantity of phosphate of lime, but the animal matter is
converted into carbon. This alteration appears to have taken place
unconnected with a high temperature, and to have been a spontaneous
change in a moist situation, to which air had no access.[31]

[31] Mr. Smee, London Med. Gazette, November 1840.

Another, and very remarkable condition, is that in which the phosphate
of lime has been removed by the infiltration of water charged with
sulphuric or carbonic acid, and the gelatin converted into leather
by tannin; as is the case with bones and teeth of deer, horses, &c.
obtained from a submerged forest of oak, larch, &c. near Ferry-bridge,
in Yorkshire; of which there are many instructive specimens in the York
Museum.[32]

[32] Communicated by Professor John Phillips.

The cancellated structure (that is, the little cells or pores) of
the long-bones of mammalia, found in caverns in England and Germany,
and in the breccia of Gibraltar, and the conglomerates of Ava and
the Sub-Himalaya mountains, &c., are often filled with crystallized
carbonate of lime. In the Wealden deposits the osseous carapaces and
plastrons of Turtles, and the bones and teeth of Crocodiles, Lizards,
&c., are almost without exception heavy, and of various shades of brown
or umber, from the infiltration of solutions of carbonates and oxides
of iron.

In some instances, bones of a jet black are imbedded in the white
calciferous grit; the phosphoric acid in the original organism having
combined with iron and produced a deep blue or black phosphate of that
mineral, and left the surrounding stone uncoloured.

Petrifaction by the infiltration of calcareous solutions is equally
common; and the medullary cavities of the bones are frequently lined
or filled with white calc-spar; brilliant pyrites also enters into the
composition of these fossils, frosting over with a golden metallic
deposit the cavities and fissures.

[Sidenote: FOSSIL BONES.]

The permeation of the teeth by mineral matter, produces beautiful
examples of the tissues of those organs; the dentine is often stained
throughout with a rich sienna tint, and sections viewed under the
microscope by transmitted light, reveal the character and distribution
of the calcigerous tubes more clearly even than in recent specimens.

It is extremely rare that osseous structures are found petrified by
flint; among the many thousands of bones which I have extracted from
the rocks, or have seen in collections, I know but of one instance of
a silicified vertebra, that of a Mosasaurus, from a chalk-pit near
Brighton; and a few bones and scales of fishes. But notwithstanding the
weight and apparent solidity imparted by these modes of mineralization,
the substance is generally rendered extremely brittle, so that the
development of the bones from the stone in which they are imbedded,
and the removal of the hard ferrugino-calcareous crust investing them,
is no easy task, but requires much tact, experience, and patience, to
execute successfully.

Hints for collecting fossil bones.--The light, friable, porous bones,
require great care in their removal from the deposit in which they
are imbedded, whether it be clay, consolidated shingle, or limestone;
if of considerable size, they will almost invariably break to pieces,
and many examples will not admit of repair. It is therefore always
desirable, before attempting to extract a large bone, to make a sketch
of it; its form will thus be known, should it be destroyed; and if it
crack into fragments that will admit of reunion, the drawing will be a
valuable guide for the replacement of the separated parts. If only a
few pieces remain, those which show any portion of the terminations,
or joints, should be preserved, as they afford the most precise and
important characters. The faithful record even of an imperfect and
unknown fossil is not without value; and as the antiquary carefully
preserves shreds of ancient manuscripts, in the hope that other
documents may one day come to light, and enable him to interpret these
now unintelligible records; so the geologist should treasure up every
fragment of an undetermined organic remain, for the time may arrive, as
I have often experienced, when specimens will be discovered that may
illustrate its nature, and prove it to be of considerable interest.

The broken porous bones may be easily repaired by a hot weak solution
of glue; and when the joinings are set, the bone should be saturated
with thin glue, well brushed in, and the surface be sponged clean with
very hot water before the cement is congealed. When dry, the specimens
will be found to possess considerable firmness and durability.[33]
By this process the tusks of mammoths and elephants may be restored,
however much crushed; time, patience, and a little dexterity, only are
required, to convert a heap of mere fragments into a valuable relic of
the ancient world.

[33] A liquid, called "Neuber's liquid glue," is an excellent cement
for this purpose: it is sold at No. 54, New Oxford Street, London.

When the bones are tolerably perfect, but dry and friable from the
loss of their animal oil, they may be made durable by saturating
them with drying oil, and exposing them to a considerable degree of
heat; in this manner the magnificent skeletons of the sloth tribe,
the Megatherium, and Mylodon, in the Hunterian Museum, were prepared.
When a bone appears as if cracked into numerous pieces before its
removal, but still preserves its form, the only method by which it can
be successfully extracted, is by spreading over it a thick layer of
plaster of Paris, which should be used of the consistence of cream;
when it sets, (which, if the plaster be recently prepared, will be in
the course of a few minutes,) the specimen may be carefully extricated,
and the plaster removed or not, according to the nature of the fossil,
and the parts to be displayed. The bones of the large reptiles which
occur in the Wealden and Oolite, may be restored in the same manner.
These remains are generally very brittle, and when imbedded in hard
grit cannot be extracted whole: they will often fall to pieces on the
slightest blow of the hammer or chisel. When of moderate size, it is
best not to attempt their removal from the stone, but to trim the block
into a convenient shape, and carefully chisel away the surrounding
part, so as to expose the essential characters of the bone. In all
cases this is an excellent method where practicable, for such specimens
have a double interest; they are at once illustrative examples of the
fossil, and of the rock in which it was deposited.

But many specimens will not admit of this method; and with large
ones it is inconvenient and undesirable, except where bones lie in
juxtaposition. The large examples in Tilgate grit, (figured in the
Fossils of Tilgate Forest,) were all extracted piecemeal from the rock:
and most of the gigantic bones of the Iguanodon, &c. now in the British
Museum, were originally in many hundred pieces, and were cemented
together with glue in the manner above described; I have found no other
method so convenient and effective.

When a bone is too imperfect to be united as a whole, it may be
imbedded in Roman cement, or plaster of Paris, which when dry may be
coloured of the prevailing tint of the rock. For large heavy specimens,
the cement is preferable; it is of easy application, and the fissures
and cracks of the bones may be filled up with it, taking care first to
cover the parts with thin hot glue, or the cement, when it dries, will
shrink and fall out. A thin coating of mastic varnish will restore the
colour, and by excluding the air, tend to preserve the specimens.

The teeth have generally undergone the same changes as the bones with
which they are associated. The teeth of elephants or mammoths that are
imbedded in loose calcareous earth, like the loam and chalk-rubble of
Brighton cliffs, and of Walton in Essex, are friable, and apt to split
and separate in the direction of the vertical plates of dentine and
bone: the pieces should be glued together, and when set, the tooth be
thoroughly saturated with thin glue, used very hot, and the superfluous
cement removed with a sponge wrung out as dry as possible from boiling
water. If there be any portion of the jaw attached to the teeth, it
must be carefully preserved; and search should be made for fragments of
the articulations, or parts of the joints and sockets.

In argillaceous strata, as the Lias-shale, London Clay, &c., the
fossils are frequently saturated with brilliant pyrites, or sulphuret
of iron; a mineral which decomposes upon exposure to the atmosphere,
and occasions the destruction of the specimens. The fossils of the Isle
of Sheppey are peculiarly obnoxious to this change.

[Sidenote: FOSSIL ANIMAL REMAINS.]

The remains of vertebrated animals in the Lias, very often occur
as skeletons more or less perfect, the entire configuration of
the original being preserved in many instances (_Bd._ pl. 7.
_Petrifactions_, p. 340). But the deposit in which they lie is
generally laminated, and the shale flakes off without great care; much
time, labour, and practice are therefore required, to obtain specimens
of any considerable size. To the late Miss Mary Anning, of Lyme Regis,
the merit is due, of having first accomplished this difficult task;