sits on a rea Hin iit nt sostiitil Dany bu aero | : i ish i EEE EEE ri PTET URT ESTE AdEA EEG SMITHSONIAN INSTITUTION LIBRARIES DRAPER FAMILY COLLECTION GIFT OF DANIEL C. DRAPER ae ae ; es a - " Pere te aw < poe ‘spoq pouypour AYsT[s Ul ouMOyspuRg poy PIO ‘p p UGH GIG ASITOT [VOIJIOA AOp]O JO Spod OY} JO Sospo OT} OITA TSN0IT} OUo\spuRg poy PIO SUIA|10A0 Jo spoq poarnqovsy OT ut Suruedo lewg °¢ “Loyejoods oy} 0} OOVJINS poyxIwU-o[ddi1 vB YA ByvIYS OY Jo souvld 04} Suyuesoad ‘auies OnL °,2 ,o *qSTYOS UBIINITY [BIO A “D ‘09 O88q C98G ‘NOILVOIMILVULY GIAVWAOFNOONA HLVULSOTII og, ‘QUIHSHMOIMUAE ‘AVEH S.AdV LS UVEN ‘LNIOd wyoors HHL LV ‘LSIHOS TVOILUAA NO DNILSAM ‘AUNITONI ATLHOIIS ‘ANOLSANVS aay 4O VLVULS “STIVITITM ‘§ AG poavisag ‘bsq ‘Tle semvep Aq Juyjupeg & mor = Se ————<$<——< nt 2 LRA A MANUAL ELEMENTARY GEOLOGY: THE ANCIENT CHANGES OF THE EARTH AND ITS INHABITANTS AS ILLUSTRATED BY GEOLOGICAL MONUMENTS. BY SIR CHARLES LYELL, M.A. FR.S. AUTHOR OF “PRINCIPLES OF GEOLOGY,” ETO. ** Tt is a philosophy which never rests—its law is progress : a point which yesterday was invisible is its goal to-day, and will be its starting-post to-morrow.’’ 2 EDINBURGH REVIEW, July, 1837. ° NUMMULITE. AMMONITE. TRILOBITE. TERTIARY. SECONDARY. PRIMARY. REPRINTED FROM THE SIXTH EDITION, GREATLY ENLARGED. Ellustrated with 750 GWoorcuts. NEW YORK: Di. ALE Feieean:@) Ny ASN, D ChOuMeP ANI Ys 846 & 348 BROADWAY. 1858. PREFACE TO THE FIFTH EDITION. Ir is now more than three years since the appearance of the last Edition of the Manual (published January, 1851). In that interval the science of Geology has been advancing as usual at a rapid pace, making it desirable to notice many new facts and opinions, and to consider their bearing on the previously acquired stock of knowledge. In my attempt to bring up the information contained in this Treatise to the present state of the science, I have added no less than 200 new Illustrations and 140 new pages of Text, which, if printed separately and in a less condensed form, might have constituted alone a volume of respectable size. To give in detail a list of all the minor corrections and changes would be tedious; but I have thought it useful, in order to enable the reader of former editions to direct his attention at once to what is new, to offer the follow- ing summary of the more important additions and alterations. Principal Additions and Alterations in the present Edition. Cuap. IX.—* The general Table of Fossiliferous strata,” formerly placed at the end of Chapter XXVIL, is now given at p. 104, that the beginner may accustom himself from the first to refer to it from time to time when studying the numerous subdivisions into which it is now necessary to separate the chronological series of rocks. The Table has been enlarged by a column of Foreign Equivalents, comprising the names and localities of some of the best known strata in other countries of con- temporaneous date with British Formations. Cuap. XIV.—XV1.—The classification of the Tertiary formations has _been adapted to the information gained by me during a tour made in the summer of 1851 in France and Belgium. ‘The results of my survey were punted in the Quarterly Journal of the Geological Society of London for al PREFACE TO THE FIFTH EDITION. 1852. In the course of my investigations I enjoyed opportunities of determining more exactly the relations of the Antwerp and the Suffolk crag, p. 173; the stratigraphical place of the Bolderberg beds near Hasselt, p. 178; that of the Limburg or Kleyn Spawen strata, p. 188 ; and of other Belgian and French deposits. In reference to some of these, the questions so much controverted of late, whether certain groups should be called Lower Miocene or Upper Eocene, are fully discussed, p. 188, et seq. In the winter of 1852, I had the advantage of examining the northern part of the Isle of Wight, in company with my friend the late lamented Professor Edward Forbes, who pointed out to me the discoveries he had just made in regard to the true position of the Hempstead series (pp. 185-192), recognized by him as the equivalent of the Kleyn Spawen or Limburg beds, and his new views in regard to the relation of various members of the Hocene series between the Hempstead and Bag- shot beds. An account of these discoveries, with the names of the new subdivisions, is given at pp. 208 et seg. ; the whole having been revised when in print by Edward Forbes. The position assigned by Mr. Prestwich to the Thanet sands, as an Eocene formation inferior to the Woolwich beds, is treated of at p. 221, and the relations of the Middle and Lower Eocene of France to various deposits in the Isle of Wight and Hampshire at p. 222 e¢ seg. In the same chapters, many figures have been introduced of characteristic or- ganic remains, not given in previous editions. Cuap. XVII.—In speaking of the Cretaceous strata, I have for the first time alluded to the position of the Pisolitic Limestone in France, and other formations in Belgium intermediate between the White Chalk and Thanet beds, p. 235. Cuar. XVII.—The Wealden beds, comprising the Weald Clay and Hastings Sands apart from the Purbeck, are in this chapter for the first time considered as belonging to the Lower Cretaceous Group, and the reasons for the change are stated at p. 263. Cuap. XIX.—Relates to “the denudation of the Weald,” or of the country intervening between the North and South Downs. It has been almost entirely rewritten, and some new illustrations introduced. Many geologists have gone over that region again and again of late years, bringing to light new facts, and speculating on the probable time, extent, and causes of so vast a removal of rock. Ihave endeavored to show how numerous haye been the periods of denudation, how vast the duration of some of them, and how little the necessity to despair of solving the prob- lem by an appeal to ordinary causation, or to invoke the aid of imagi- nary catastrophes and paroxysmal violence, pp. 271-290. Cuap. XX.—XXI.—On the strata from the Qolite to the Lias inclu- sive. The Purbeck beds are here for the first time considered as the uppermost member of the Oolite, in accordance with the opinions of the PREFACE TO THE FIFTH EDITION. vil late Professor E. Forbes, p. 294. Many new figures of fossils character- istic of the subdivisions of the three Purbecks are introduced ; and the discovery, in 1854, of a new mammifer alluded to, p. 295. Representations also of fossils of the Upper, Middle, and Lower Oolite, and of the Lias, are added to those before given. Cuap. XXIJ—XXIII.—On the Triassic and Permian formations. The improvements consist chiefly of new illustrations of fossil remains. Carp. XXIV.—XXV.—Treating of the Carboniferous group, I have mentioned the subdivisions now generally adopted for the classification of the Irish strata (p. 359), and I have added new figures of fossil plants to explain, among other topics, the botanical characters of Calamites, Stern- bergia, and Trigonocarpum, and their relation to Conifers (pp. 364, 365, 368). The grade also of the Conifer in the vegetable kingdom, and whether they hold a high or a low position among flowering plants, is dis- cussed with reference to the opinions of several of the most eminent living botanists ; and the bearing of these views on the theory of progres- sive development, p. 370. The casts of rain-prints in coal-shale are represented in several wood- cuts as illustrative of the nature and humidity of the carboniferous atmosphere, p. 381. The causes also of the purity of many seams of coal, p. 382, and the probable length of time which was required to allow the solid matter of certain coal-fields to accumulate, p. 383, are discussed for the first time. Figures are given of Crustaceans and Insects from the Coal, pp. 385, 386; and the discovery of some new Reptiles is alluded to, p. 401. I have also alluded to the causes of the rarity of vertebrate and inver- tebrate air-breathers in the coal, p. 401. That division of this same chapter (Chap. XXV.) which relates to the Mountain Limestone has been also enlarged by figures of new fossils, and among others by representations of Corals of the Paleozoic, as distin- guishable from those of the Neozoic, type, p. 408 ; also by woodcuts of several genera of shells which retain the patterns of their original colors, p- 406. The foreign equivalents of the Mountain Limestone are also alluded to, p. 409. Cap. XXVI—In speaking of the Old Red Sandstone, or Devonian Group, the evidence of the occurrence of the skeleton of a Reptile and the footprints of a Chelonian in that series are reconsidered, p. 412. New plants found in Ireland in this formation are figured, p. 414; also the Pterygotus, or large crustacean of Forfarshire, p. 415 ; and, lastly, the division of the Devonian series in North Devon into Upper, Middle, and Lower, p. 420, the fossils of the same (p. 421 et seq.), and the equivalents of the Devonian beds in Russia and the United States, are treated of, p. 425 and 428. Cuar. XXVII.—The classification and nomenclature of the Silurian rocks of Great Britain, the Continent of Europe, and North America, and the question whether they can be distinguished from the Cambrian, and Vill PREFACE TO THE FIFTH EDITION. by what paleontological characters, are discussed in this chapter, pp. 429, 447, and 458. The relation of the Caradoc Sandstone to the Upper and Lower Silu- rian, as inferred from recent investigations (p. 437), the vast thickness of the Llandeilo or Lower Silurian in Wales (p. 442), the Obolus or Ungu- lite grit of St. Petersburg and its fossils (p. 443), the Silurian strata of the United States and their British equivalents (p. 444), and those of Canada, the discoveries of M. Barrande respecting the metamorphosis of Silurian and Cambrian trilobites (pp. 441, 450), are among the subjects enlarged upon more fully than in former editions, or now treated of for the first time. The Cambrian beds below the Llandeilo, and their fossils, are likewise described as they exist in Wales, Ireland, Bohemia, Sweden, the United States, and Canada, and some of their peculiar organic remains are fig- ured, p. 447 to p. 453. Lastly, at the conclusion of the chapter, some remarks are offered re- specting the absence of the remains of fish and other vertebrata from the deposits below the Upper Silurian, p. 453, in elucidation of which topic a Table has been drawn up of the dates of the successive discovery of dif- ferent classes of Fossil Vertebrata in rocks of higher and higher anti- quity, showing the gradual progress made in the course of the last century and a half in tracing back each class to more and more ancient rocks. The bearing of the positive and negative facts thus set forth on the doctrine of progressive development is then discussed, and the grounds of the supposed scarcity both of vertebrate and invertebrate air- breathers in the most ancient formation considered, p. 456. Cuar. XXVII.—With the assistance of an able mineralogis¢, M. Delesse, I have revised and enlarged the glossary of the more abundant voleanic rocks, p. 472, and the table of analyses of simple minerals, p: 475. Cuap. XXIX.—In consequence of a geological excursion to Madeira and the Canary Islands, which I made in the winter of 1853-4, I have been enabled to make larger additions of original matter to this chapter than te any other in the work. The account of Teneriffe and Madeira, pp: 510, 518, is wholly new. Formerly I gave an abstract of Von Buch’s description of the island of Palma, one of the Canaries, but I have now treated of it more fully from my own observations, regarding Palma as a good type of that class of volcanic mountains which have been called by Von Buch “craters of elevation,” pp. 494-508. Many illustrations, chiefly from the pencil of my companion and fellow-laborer, Mr. Hartung, have been introduced. In reference to the above-mentioned subjects, citations are made from Dana on the Sandwich Islands, p. 489, and from Junghuhn’s Java, p. 492. Cuar. XXXV.—XXXVII.—The theory of the origin of the meta- morphic rocks and certain views recently put forward by some geolo- gists respecting cleavage and foliation have made it desirable to recast PREFACE TO THE FIFTH EDITION. 1x and rewrite a portion of these chapters. New proofs are cited in favor of attributing cleavage to mechanical force, p. 603, and for inferring in many cases 2 connection between foliation and cleavage, p. 608. At the same time, the question—how far the planes of foliation usually agree with those of sedimentary deposition, is entered into, p. 607. Cuarp. XXXVIII—To the account formerly published of mineral veins, some facts and opinions are added respecting the age of the rocks and alluvial deposits containing gold in South America, the United States, California, and Australia. I have already alluded to the assistance afforded me by the late Professor Edward Forbes towards the improvement of some parts of this work. His letters suggesting corrections and additions were continued to within a few weeks of his sudden and unexpected death, and I felt most grateful to him for the warm interest, which, in the midst of so many and pressing avocations, he took in the success of my labors. His friendship, and the power of referring to his sound judgment in cases of difficulty on paleontological and other questions, were among the highest privileges I have ever enjoyed in the course of my scientific pursuits. Never perhaps has it been the lot of any Englishman, who had not attained to political or literary eminence, more especially one who had not reached his fortieth year, to engage the sympathies of so wide a circle of admirers, and to be so generally mourned. The untimely death of such a teacher was justly felt to be a national loss; for there was a deep conviction in the minds of all who knew him, that genius of so high an order, combined with vast acquirements, true independence of character, and so many social and moral ex- cellences, would have inspired a large portion of the rising generation with kindred enthusiasm for branches of knowledge nitherto neglected in the education of British youth. As on former occasions, I shall take this opportunity of stating that the “ Manual” is not an epitome of the “ Principles of Geology,” nor intended as introductory to that work. So much confusion has arisen on this subject, that it is desirable to explain fully the different ground occupied by the two pub- | ications. The first five editions of the “ Principles” comprised a 4th book, in which some account was given of systematic x PREFACE TO THE FIFTH EDITION. geology, and in which the principal rocks composing the earth’s crust and their organic remains were described. In subsequent editions this 4th book was omitted, it having been expanded, 1838, into a separate treatise called the ‘‘ Elements — of Geology,” first re-edited in 1842, and again recast and en- larged in 1851, and entitled ‘“‘ A Manual of Elementary Geol- ogy.” Of this enlarged work another edition, called the Fourth, was published in 1852. . Although the subjects of both treatises relate to Geology, as their titles imply, their scope is very different; the ‘ Princi- ples” containing a view of the modern changes of the earth and its inhabitants, while the ‘“‘ Manual” relates to the monuments of ancient changes. In separating the ene from the other, I have endeavored to render each complete in itself, and inde- pendent; but if asked by a student which he should read first, I would recommend him to begin with the “ Principles,” as he may then proceed from the known to the unknown, and be provided beforehand with a key for interpreting the ancient phenomena, whether of the organic or inorganic world, by reference to changes now in progress. It will be seen on comparing ‘‘ The Contents” of the “* Prin- eiples” with the abridged headings of the chapters of the present work (see the following pages), that the two treatises have but little in common; or, to repeat what I have said in the Preface to the ‘‘ Principles,” they have the same kind of connection which Chemistry bears to Natural Philosophy, each being subsidiary to the other, and yet admitting of being con- sidered as different departments of science.* CHARLES LYELL. 58 Harley-street, London, February 22, 1855. * As it is impossible to enable the reader to recognize rocks and minerals at sight by aid of verbal descriptions or figures, he will do well to obtain a well- arranged collection of specimens, such as may be procured from Mr. Tennant (149 Strand), teacher of Mineralogy at King’s College, London, CONTENTS. Cuaprer I—On the different Classes of Rocks. Geology defined—Successive formation of the earth’s crust—Classification of rocks according to their origin and age—Aqueous rocks—Volcanic rocks— Plutonie rocks—Metamorphic rocks—The term primitive, why erroneously applied to the crystalline formations — - - - - Page 1 Cuarter IL—Agueous Rocks—Their Composition and Forms of Stratification. Mineral composition of strata—Arenaceous rocks—Argillaceous—Calcareous— Gypsum—Forms of stratification—Diagonal arrangement—Ripple-mark 10 Cuarter I1L—Arrangement of Fossils in Strata—Freshwater and Marine. Limestones formed of corals and shells—Proofs of gradual increase of strata de- rived from fossils—Tripoli and semi-opal formed of infusoria—Chalk derived principally from organic bodies—Distinction of freshwater from marine forma- tions—Alternation of marine and freshwater deposits - - Sal Cuaprer LV.—Consolidation of Strata and Petrifaction of Fossils. Chemical and mechanical deposits—Cementing together of particles—Concre- tionary nodules—Consolidating effects of pressure—Mineralization of organic remains—Impressions and casts how formed—Fossil wood—Source of lime and silex in solution - - = = - 2 - - 33 Caarter V.—Llevation of Strata above the Sea—Horizontal and Inclined Stratification. Position of marine strata, why referred to the rising up of the land, not to the going down of the sea—Upheaval of horizontal strata—Inclined and vertical stratification—Anticlinal and synclinal lines—Theory of folding by lateral moyement—Creeps—Dip and strike—Structure of the Jura—Inverted posi- tion of disturbed strata—Unconformable stratification—Fractures of strata— Faults - 5 - - 7 ; - 2 - 44 CuarterR V1I.—Denudation: Denudation defined—Its amount equal to the entire mass of stratified deposits in the earth’s crust—Levelled surface of countries in which great faults occur— Denuding power of the ocean—Origin of Valleys—Obliteration of sea-cliffs— Inland sea-cliffs and terraces - - - - - - 66 Cuarrer VIL—Alluvium. Alluvium described—Due to complicated causes—Of various ages—How distin- guished from rocks in situ—River-terraces—Parallel roads of Glen Roy ‘79 Cuapter VIIIL—Chronological Classification of Rocks. Aqueous, plutonic, voleanic, and metamorphic rocks, considered chronologically —Lehman’s division into primitive and secondary—Werner’s addition of a transition class—Neptunian theory—Hutton on igneous origin of granite— The name of “primary” for granite and the term “ transition” why faulty— Chronological nomenclature adopted in this work, so far as regards primary, secondary, and tertiary periods - - - - - - 89 xii CONTENTS. Cuaprer 1X.—On the different Ages of the Aqueous Rocks. On the three tests of relative age—superposition, mineral character, and fossils— Change of mineral character and fossils in the same formation—Proofs that distinct species of animals and plants have lived at successive periods—Dis- tinet provinces of indigenous species—Similar laws prevailed at successive geological periods—Test of age by included fragments—Frequent absence of strata of intervening periods—General Table of Fossiliferous strata Page 96 Cuapter X.—Classification of Tertiary Formations —Post Pliocene Group. General principles of classification of tertiary strata—Difficulties in determining their chronology—Increasing proportion of living species of shells in strata of newer origin—Terms Eocene, Miocene, and Pliocene—Post-Pliocene recent strata : - : = 2 - = 2 - 109 Cuaprrer XI.—Newer Pliocene Period.—Boulder Formation. Drift of Scandinavia, northern Germany, and Russia—Fundamental rocks pol- ished, grooved, and scratched—Action of glaciers and icebergs—Fossil shells of glacial period—Drift of eastern Norfolk—Ancient glaciers of North Wales —lIrish drift - - - - - - - - 126 Cuarrer XI]L—Boulder Formation—continued. Effects of intense cold in augmenting the quantity of alluvium— & Y Chalk a SEG HOY a Chalk, IO GTZIPOYePeDODaA BCR Sand-pipes in the chalk at Eaton, near Norwich. 1839, laid open in a large chalk-pit near Norwich. They were of very symmetrical form, the largest more than 12 feet in diameter, and some of them had been traced, by boring, to the depth of more than 60 feet. The smaller ones varied from a few inches to a foot in diameter, and seldom descended more than 12 feet below the surface. Even where three of them occurred, as at a, fig. 101, very close together, the parting walls of soft white chalk were not broken through. They all taper downwards and end in a point. As a general rule, sand and pebbles occupy the central parts of each pipe, while the sides and bottom are lined with clay. Mr. Trimmer, in speaking of appearances of the same kind in the Kentish chalk, attributes the origin of such “sand-galls” to the action of the sea on a beach or shoal, where the waves, charged with shingle and sand, not only wear out longitudinal furrows, such as may be ob- served on the surface of the above-mentioned chalk near Norwich when the incumbent gravel is removed, but also drill deep circular hollows by the rotatory motion imparted to sand and pebbles. Such furrows, as well as vertical cavities, are now formed, he observes, on the coast where the shores are composed of chalk.* That the commencement of many of the tubular cavities now under consideration has been due to the cause here assigned, I have little doubt, But such mechanical action could not have hollowed out the whole of ‘the sand-pipes ¢ and d, fig. 101, because several large chalk-flints seen protruding from the walls of the pipes have not been eroded, while sand :and gravel have penetrated many feet below them. In other cases, as * Trimmer, Proceedings of Geol. Soe. vol. iv. p. 7, 1842. Cx. VIL] ALLUVIUM. 83 at 6 b, similar unrounded nodules of flint, still preserving their irregular form and white coating, are found at various depths in the midst of the leose materials filling the pipe. These have evidently been detached from regular layers of flints occurring above. It is also to be remarked that the course of the same sand-pipe, 6 4, is traceable above the level of the chalk for some distance upwards, through the incumbent gravel and sand, by the obliteration of all signs of stratification. Occasionally, also, as in the pipe d, the overlying beds of gravel bend downwards into the mouth of the pipe, so as to become in part vertical, as would happen if horizontal layers had sunk gradually in consequence of a failure of support. All these phenomena may be accounted for by attributing the enlargement and deepening of the sand-pipes to the chemical action of water charged with carbonic acid, derived from the vegetable soil and the decaying roots of trees. Such acid might corrode the chalk, smd deepen indefinitely any previously existing hollow, but could not dissolve the flints. The water, after it had become saturated with carbonate of lime, might freely percolate the surrounding porous walls of chalk, and escape through them and from the bottom of the tube, so as to carry away in the course of time large masses of dissolved calcareous rock,* and leave behind it on the edges of each tubular hollow a coating of fine day, which the white chalk contains. I have seen tubes precisely similar and from 1 to 5 feet in diameter traversing vertically the upper half of the soft calcareous building-stone, or chalk without flints, constituting St. Peter’s Mount, Maestricht. These hollows are filled with pebbles and clay, derived from overlying beds of gravel, and all terminate downwards like those of Norfolk. I was in- formed that, 6 miles from Maestricht, one of these pipes, 2 feet in diam- eter, was traced downwards to a bed of flattened flints, forming an almost continuous layer in the chalk. Here it terminated abruptly, but a few small root-like prolongations of it were detected immediately below, probably where the dissolving substance had penetrated at some points through openings in the siliceous mass. It is not so easy as may at first appear to draw a clear line of distine- tion between the fixed rocks, or regular strata (rocks in situ or in place), and alluvium. If the bed of a torrent or river be dried up, we call the gravel, sand, and mud left in their channels, or whatever, during floods, they may have scattered over the neighboring plains, alluviwm. The very same materials carried into a lake, where they become sorted by water and arranged in more distinct layers, especially if they inclose the remains of plants, shells, or other fossils, are termed regular strata. In like manner we may sometimes compare the gravel, sand, and broken shells, strewed along the path of a rapid marine current, with a deposit formed contemporaneously by the discharge of similar materials, year after year, into a deeper and more tranquil part of the sea. In such cases, when we detect marine shells cr other organic remains en- * See Lyell on Sand-pipes, &c. Phil. Mag. third series, vol. xv. p. 257, Oct, 1839. 84 ‘ALLUVIUM. (Cz. VIL tombed in the strata, which enable us to determine their age and mode of origin, we regard them as part of the regular series of fox siliferous formations, whereas, if there are no fossils, we have frequently no power of separating them from the general mass of superficial al- luvium. The usual rarity of organic remains in beds of loose gravel is partly owing to the friction which originally ground down rocks into pebbles or sand, and organic bodies into small fragments, and it is partly owing to the porous nature of alluvium when it has emerged, which allows the free percolation through it of rain-water, and promotes the decomposition and solution of fossil remains. It has long been a matter of common observation that most rivers are now cutting their channels through alluvial deposits of greater depth and extent than could ever have been formed by the present streams. From this fact a rash inference has sometimes been drawn, that rivers in general have grown smaller, or become less liable to be flooded than for- merly. But such phenomena would be a natural result of considerable oscillations in the level of the land experienced since the existing valleys originated. Suppose part of a continent, comprising within it a large hydrographical basin like that of the Mississippi, to subside several inches or feet in a century, as the west coast of Greenland, extending 600 miles north and south, has been sinking for three or four centuries, between the latitudes 60° and 69° N.* It will rarely happen that the rate of subsidence will be everywhere equal, and in many cases the amount of depression in the interior will regularly exceed that of the region nearer the sea. Whenever this happens, the fall of the waters flowing from the upland country will be diminished, and each tributary stream will haye less power .to carry its sand and sediment into the main river, and the main river less power to convey its annual burden of transported matter to the sea. All the rivers, therefore, will proceed to fill up partially their ancient channels, and, during frequent inundations, will raise their alluvial plains by new deposits. If then the same area of land be again upheaved to its former height, the fall, and consequently the velocity, of every river would begin to aug- ment. Each of them would be less given to overflow its alluvial plain ; and their power of carrying earthy matter seaward, and of scouring out and deepening their channels, will be sustained till, after a lapse of many thousand years, each of them has eroded a new channel or valley through _ a fluviatile formation of comparatively modern date. The surface of what was once the river-plain at the period of greatest depression, will then remain fringing the valley sides in the form of a terrace apparently flat, but in reality sloping down with the general inclination of the river. Everywhere this terrace will present cliffs of gravel and sand, facing the river. That such a series of movements has actually taken place in the main valley of the Mississippi and in its tributary valleys during * Principles of Geology, 7th ed. p. 506, 8th ed. p. 509. Cu. VIL] RIVER TERRACES. 85 oscillations of level, I have endeavored to show in my description of that country ;* and the freshwater shells of existing species and bones of land quadrupeds, partly of extinct races preserved in the terraces of flu- viatile origin, attest the exclusion of the sea during the whole process of filling up and partial re-excavation. ~ , Im many cases, the alluvium in which rivers are now cutting their channels, originated when the land first rose out of the sea. — If, for ex- ample, the emergence was caused by a gradual and uniform motion, every bay and estuary, or the straits between islands, would dry up slowly, and during their conversion into valleys, every part of the up- heayed area would in its turn be'a sea-shore, and might be strewed over with littoral sand and pebbles, or each spot might be the point where a delta accumulated during the retreat and exclusion of the sea. Mate- rials so accumulated would conform to the general slope of a valley from its head to the sea-coast. River terraces.—We often observe at a short distance from the present bed of a river a steep cliff a few feet or yards high, and on a level with the top of it a flat terrace corresponding in appearance to the alluvial plain which immediately borders the river. This terrace is again bounded by another cliff, above which a second terrace sometimes occurs: and in this manner two or three ranges of cliffs and terraces are occasionally seen on one or both sides of the stream, the number varying, but those on the opposite sides often corresponding in height. River Terraces and Parallel Roads. These terraces are seldom continuous for great distances, and their surface slopes downwards, with an inclination similar to that of the river. They are readily explained if we adopt the hypothesis before suggested, of a gradual rise of the land; especially if, while rivers are shaping out their beds, the upheaving movement be intermittent, so that long pauses shall occur, during which the stream will have time to encroach upon one of its banks, so as to clear away and flatten a large space. This * Second Visit to the U. S., vol. ii. chap. 34. 86 PARALLEL ROADS [Cu. VIL operation being afterwards repeated at lower levels, there will be several successive cliffs and terraces. Parallel roads——The parallel shelves, or roads, as they have been called, of Lochaber or Glen Roy and other contiguous valleys in Scot- land, are distinct both in character and origin from the terraces above described ; for they have no slope towards the sea like the channel of a river, nor are they the effect of denudation. Glen Roy is situated in the western Highlands, about ten miles north of Fort William, near the western end of the great glen of Scotland, or Caleconian Canal, and near the foot of the highest of the Grampians, Ben Nevis. Throughout its whole length, a distance of more than ten miles, twe, and in its lower part three, parallel roads or shelves are traced along the steep sides of the mountains, as represented in the annexed figure (fig. 102), each maintaining a perfect horizontality, and continuing at exactly the same level on the opposite sides of the glen. Seen at a distance, they appear like ledges or roads, cut artificially out of the sides of the hills; but when we are upon them we can scarcely recognize their existence, so uneven is their surface, and so covered with boulders. They are from 10 to 60 feet broad, and merely differ from the side of the mountain by being somewhat less steep. On closer inspection, we find that these terraces are stratified in the ordinary manner of alluvial or littoral deposits, as may be seen at those points where ravines have been excavated by torrents. The parallel shelves, therefore, have not been caused by denudation, but by the depo- sition of detritus, precisely similar to that which is dispersed in smaller quantities over the declivities of the hills above. These hills consist of clay-slate, mica-schist, and granite, which rocks have been worn away and Jaid bare at a few points only, in a line just above the parallel roads. The highest of these roads is about 1250 feet above the level of the sea, the next about 200 feet lower than the uppermost, and the third still lower by about 50 feet. It is only this last, or the lowest of the three, which is continued throughout Glen Spean, a large valley with which Glen Roy unites. As the shelves are always at the same height above the sea, they become continually more elevated above the river in pro- portion as we descend each valley; and they at length terminate very abruptly, without any obvious cause, or any change either in the shape of the ground, or in the composition or hardness of the recks. I should exceed the limits of this work, were I to attempt to give a full descrip- tion of all the geographical circumstances attending these singular ter- races, or to discuss the ingenious theories which have been severally proposed to account for them by Dr. MacCuiloch, Sir T. D. Lauder, and Messrs. Darwin, Agassiz, Milne, and Chambers. There is one point, however, on which all are agreed, namely, that these shelves are ancient beaches, or littoral formations accumulated round the edges of one or more sheets of water which once stood at the level, first of the highest shelf, and successively at the height of the two others. It is well known, that wherever a lake or marine fiord exists surrounded by steep moun- Cu. VIL] OF GLEN ROY. 87 tains subject to disintegration by frost or the action of torrents, some loose matter is washed down annually, especially during the melting of snow, and a cheek is given to the descent of this detritus at the point where it reaches the waters of the lake. The waves then spread out the materials along the shore, and throw some of them upon the beach ; their dispersing power being aided by the ice, which often adheres to pebbles during the winter months, and gives buoyancy to them. The annexed diagram illustrates the manner in which Dr. MacCulloch and Mr. Darwin AB. Supposed original surface of — spose “the roads” to constitute mere in- Gers Hosdscr se ena dentations in a superficial alluvial coating which rests upon the hill-side, and consists chiefly of clay and sharp unrounded stones. Among other proofs that the parallel roads have really been formed along the margin of a sheet of water, it may be mentioned, that wher- ever an isolated hill rises in the middle of the glen above the level of any particular shelf, a corresponding shelf is seen at the tame level passing round the hill, as would have happened if it had once formed an island in a lake or fiord. Another very remarkable peculiarity in these terraces is this; each of them comes in some portion of its course to a col, or passage between the heads of glens, the explanation of which will be considered in the sequel. Those writers who first advocated the doctrine that the roads were the ancient beaches of freshwater lakes, were unable to offer any probable hypothesis respecting the formation and subsequent removal of barriers of sufficient height and solidity to dam up the water. To introduce any violent convulsion for their removal was inconsistent with the unin- terrupted horizontality of the roads, and with the undisturbed aspect of those parts of the glens where the shelves come suddenly to an end. Mr. Agassiz and Dr. Buckland, desirous, like the defenders of the lake theory, to account for the limitation of the shelves to certain glens, and their absence in contiguous glen’, where the rocks are of the same com- position, and the slope and inclination of the ground very similar, started the conjecture that these valleys were once blocked up by enormous gla- ciers descending from Ben Nevis, giving rise to what are called in Swit- zerland and in the Tyrol, glacier-lakes. After a time the icy barrier was broken down, or melted, first, to the level of the second, and after- wards to that of the third road or shelf. In corroboration of this view, they contended that the alluvium of Glen Roy, as well as of other parts of Scotland, agrees in character with the moraines of glaciers seen in the Alpine valleys of Switzerland. Al- Jusion will be made in the eleventh chapter to the former existence of glaciers in the Grampians: in the mean time it will readily be conceded that this hypothesis is preferable to any previous lacustrine theory, by Fig. 108. 88 PARALLEL ROADS OF GLEN ROY. [Cu. VIL accounting more easily for the temporary existence and entire disappear- ance of lofty transverse barriers, although the height required for the im- aginary dams of ice may be startling. Before the idea last alluded to had been entertained, Mr. Darwin examined Glen Roy, and came to the opinion that the shelves were formed when the glens were still arms of the sea, and consequently, that there never were any seaward barriers. According to him, the land emerged during a slow and uniform upward movement, like that now experienced throughout a large part of Sweden and Finland; but there were certain pauses in the upheaving process, at which times the waters of the sea remained station- ary for so many centuries as to allow of the accumulation of an extraor- dinary quantity of detrital matter, and the excavation, at many points im- mediately above, of deep notches and bare cliffs in the hard and solid rock. The phenomena which are most difficult to reconcile with this theory are, first, the abrupt cessation of the roads at certain points in the different glens ; secondly, their unequal number in different valleys connecting with each other, there being three, for example, in Glen Roy and only one in Glen Spean; thirdly, the precise horizontality of level maintained by the same shelf over a space many leagues in length requiring us to assume, that during a rise of 1250 feet no one portion of the land was raised even a few yards above another; fourthly, the coincidence of level already al- luded to of each shelf with a col, or the point forming the head of two glens, from which the rain-waters flow in opposite directions. This last- mentioned feature in the physical geography of Lochaber seems to have been explained in a satisfactory manner by Mr. Darwin. He calls these cols “ landstraits,” and regards them as having been anciently sounds or channels between islands. He points out that there is a tendency in such sounds to be silted up, and always the more so in proportion to their nar- rowness. Ina chart of the Falkland Islands by Capt. Sullivan, R. N., it appears that there are several examples there of straits where the sound- ings diminish regularly towards the narrowest part. One is so nearly dry that it can be walked over at low water, and another, no longer covered by the sea, is supposed to have recently dried up in consequence of a small alteration in the relative level of sea and land. “Similar straits,” observes Mr. Chambers, “ hovering, in character, between sea and land, and which may be called fords, are met with in the Hebrides. Such, for example, is the passage dividing the islands of Lewis and Harris, and that between North Uist and Benbecula, both of which would undoubtedly appear as cols, coinciding with a terrace or raised beach, all round the islands, if the sea were to subside.”* The first of the difficulties above alluded to, namely, the non-extension of the shelves over certain parts of the glens, may be explained, as Mr. Darwin suggests, by supposing in certain places a quick growth of green turf on a good soil, which prevented the rain from washing away any loose materials lying on the surface. But wherever the soil was barren, and where green sward took long to form, there may have been time for the removal of * “ Ancient Sea Margins,” p. 114, by R. Chambers. Cx, VIL] CHRONOLOGY OF ROCKS. Sg the gravel. In one case an intermediate shelf appears for a short distance (three quarters of a mile) on the face of the mountain called Tombhran, between the two upper shelves, and is seen nowhere else. It occurs where there was the longest space of open water, and where, perhaps, the waves acquired a greater than ordinary power in heaping up detritus. Next as to the precise horizontality of level maintained by the parallel roads of Lochaber over an area many leagues in length and breadth, this is a difficulty common in some degree to all the rival hypotheses, whether of lakes or glaciers, or of the simple upheaval of the land above the sea. For we cannot suppose the roads to be more ancient than the glacial period, or the era of the boulder formation of Scotland, of which I shall speak in the eleventh and twelfth chapters. Strata of that era of marine origin containing northern shells of existing species have been found at various heights in Scotland, some on the east and others on the west ‘coast, from 20 to 400 feet high; and in one region in Lanarkshire not less than 524 feet above high-water mark. It seems, therefore, in the highest degree improbable that Glen Roy should have escaped entirely the upward movement experienced in so many surrounding regions,—a movement implied by the position of these marine deposits, in which the shells are almost all of known recent species. But if the motion has really extended to Glen Roy and the contiguous glens, it must have up- lifted them bodily, without in the slightest degree affecting their horizon- tality ; and this being admitted, the principal objection to the theory of marine beaches, founded on the uniformity of upheaval, is removed, or is at least common to every theory hitherto proposed. To assume that the ocean has gone down from the level of the upper- most shelf, or 1250 feet, simultaneously all over the globe, while the land remained unmoved, is a view which will find favor with very few geolo- gists, for the reasons explained in the fifth chapter. The student will perceive, from the above sketch of the controversy re- specting the formation of these curious shelves, that this problem, like many others in geology, is as yet only solved in part; and that a larger number of facts must be collected and reasoned upon before the question can be finally settled. CHAPTER VIII. CHRONOLOGICAL CLASSIFICATION OF ROCKS. Aqueous, plutonic, volcanic, and metamorphic rocks, considered chronologically— Lehman’s division into primitive and secondary—Werner’s addition of a tran- sition class—Neptunian theory—Hutton on igneous origin of granite—How the name of primary was still retained for granite—The term “ transition,” why faulty—The adherence to the old chronological nomenclature retarded the progress of geology—New hypothesis intended to reconcile the igneous origin of granite to the notion of its high antiquity—Explanation of the chronological nomenclature adopted in this work, so far as regards primary, secondary, and tertiary periods. 90 CLASSIFICATION OF ROCKS. [Cu. VIL In the first chapter it was stated that the four great classes of rocks, the aqueous, the volcanic, the plutonic, and the metamorphic, would each be — considered not only in reference to their mineral characters, and mode of ori- gin, but also to their relative age. In regard to the aqueous rocks, we have already seen that they are stratified, that some are calcareous, others argil- laceous or siliceous, some made up of sand, others of pebbles ; that some contain freshwater, others marine fossils, and so forth ; but the student has still to learn which rocks, exhibiting some or all of these characters, have originated at one period of the earth’s history, and which at another. To determine this point in reference to the fossiliferous formations is more easy than in any other class, and it is therefore the most convenient and natural method.to begin by establishing a chronology for these strata, and then to refer as far as possible to the same divisions the several groups of plutonic, volcanic, and metamorphic rocks. Such a system of classifica- tion is not only recommended by its greater clearness and facility of ap- plication, but is also best fitted to strike the imagination by bringing into one view the contemporaneous revolutions of the inorganic and organic creations of former times. For the sedimentary formations are most readily distinguished by the different species of fossil animals and plants which they inclose, and of which one assemblage after another has flourished and then disappeared from the earth in succession. But before entering specially on the subdivisions of the aqueous rocks arranged according to the order of time, it will be desirable to say a few words on the chronology of rocks in general, although in doing so we shall be unavoidably led to allude to some classes of phenomena which the beginner must not yet expect fully to comprehend. It was for many years a received opinion, that the formation of entire families of rocks, such as the plutonic and those crystalline schists spoken of in the first chapter as metamorphic, began and ended before any mem- bers of the aqueous and volcanic orders were produced ; and although this idea has long been modified, and is nearly exploded, it will be neces- sary to give some account of the ancient doctrine, in order that beginners may understand whence many prevailing opinions, and some part of the nomenclature of geology, still partially in use, was derived. About the middle of the last century, Lehman, a German miner, pro- posed to divide rocks into three classes, the first and oldest to be called primitive, comprising the hypogene, or plutonic and metamorphic rocks ; the next to be termed secondary, comprehending the aqueous or fossilif- erous strata; and the remainder, or third class, corresponding to our alluvium, ancient and modern, which he referred to “local floods, and the deluge of Noah.” In the primitive class, he said, such as granite and gneiss, there are no organie remains, nor any signs of materials de- rived from the ruins of pre-existing rocks. Their origin, therefore, may have been purely chemical, antecedent to the creation of living beings, and probably coeval with the birth of the world itself. The secondary formations, on the contrary, which often contain sand, pebbles, and or- ganic remains, must have been mechanical deposits, produced after the Cs. VIIL] NEPTUNIAN THEORY. 91 planet had become the habitation of animals and plants. This bold generalization, although anticipated in some measure by Steno, a century before, in Italy, formed at the time an important step in the progress of geology, and sketched out correctly some of the leading divisions into which rocks may be separated. About half a century later, Werner, so justly celebrated for his improved methods of discriminating the minera- logical characters of rocks, attempted to improve Lehman’s classification, and with this view intercalated a class, called by him “the transition formations,” between the primitive and secondary. Between these last he had discovered, in northern Germany, a series of strata, which in their mineral peculiarities were of an intermediate character, partaking in some degree of the crystalline nature of micaceous schist and clay-slate, and yet exhibiting here and there signs of a mechanical origin and or- ganic remains. For this group, therefore, forming a passage between Lehman’s primitive and secondary rocks, the name of ibergang or transi- tion was proposed. ‘They consisted principally of clay-slate and an ar- gillaceous sandstone, called grauwacke, and partly of calcareous beds. It happened in the district which Werner first investigated, that both the primitive and transition strata were highly inclined, while the beds of the newer fossiliferous rocks, the secondary of Lehman, were horizontal. To these latter therefore, he gave the name of /létz, or “a level floor ;” and every deposit more modern than the chalk, which was classed as the uppermost of the flétz series, was designated “ the overflowed land,” an expression which may be regarded as equivalent to alluvium, although under this appellation were confounded all the strata afterwards called tertiary, of which Werner had scarcely any knowledge. As the followers of Werner soon discovered that the inclined position of the “ transition beds,” and the horizontality of the flétz, or newer fossiliferous strata, were mere locai accidents, they soon abandoned the term flétz; and the four divisions of the Wernerian school were then named primitive, transition, secondary, and alluvial. As to the trappean rocks, although their igneous origin had been al- ready demonstrated by Arduino, Fortis, Faujas, and others, and especially by Desmarest, they were all regarded by Werner as aqueous, and as mere subordinate members of the secondary series.* The theory of Werner’s was called the “ Neptunian,” aad for many years enjoyed much popularity. It assumed that the globe had been at first invested by a universal chaotic ocean, holding the materials of all rocks in solution. From the waters of this ocean, granite, gneiss, and other crystalline formations, were first precipitated; and afterwards, when the waters were purged of these ingredients, and more nearly resembled those of our actual seas, the transition strata were deposited. These were of a mixed character, not purely chemical, because the waves and currents had already begun to wear down solid land, and to give rise to pebbles, sand, and mud; nor entirely without fossils, because a few of the first marine animals had begun to exist. After this period, the secondary for- * See Principles of Geology, vol. i. chap. iv. 92 ON THE TERM “ TRANSITION.” [Ca. VIL mations were accumulated in waters resembling those of the present ocean; except at certain intervals, when, from causes wholly unexplained, a par- tial recurrence of the “chaotic fluid” took place, during which various trap rocks, some highly crystalline, were formed. This arbitrary hypothe- sis rejected all intervention of igneous agency, volcanoes being regarded as modern, partial, and superficial accidents, of trifling account among the great causes which have modified the external structure of the globe. Meanwhile Hutton, a contemporary of Werner, began to teach, in Scotland, that granite as well as trap was of igneous origin, and had at various periods intruded itself in a fluid state into different parts of the earth’s crust.. He recognized and faithfully described many of the phe- nomena of granitic veins, and the alterations produced by them on the invaded strata, which will be treated of in the thirty-third chapter. He, moreover, advanced the opinion, that the crystalline strata called primi- tive had not been precipitated from a primeeval ocean, but were sediment- ary strata altered by heat. In his writings, therefore, and in those of his illustrator, Playfair, we find the germ of that metamorphic theory which has been already hinted at in the first chapter, and which will be more fully expounded in the thirty-fourth and thirty-fifth chapters. At length, after much controversy, the doctrine of the igneous origin of trap and granite made its way into general favor; but although it was, in consequence, admitted that both granite and trap had been produced at many successive periods, the term primitive or primary still continued to be applied to the crystalline formations in general, whether stratified, like gneiss, or unstratified, like granite. The pupil was told that granite was a primary rock, but that some granites were newer than certain secondary formations ; and in conformity with the spirit of the ancient language, to which the teacher was still determined to adhere, a desire was naturally engendered of extenuating the importance of those more modern granites, the true dates of which new observations were continually bringing to light. A no less decided inclination was shown to persist in the use of the term “ transition,” after it had been proved to be almost as faulty in its original application as that of flétz. The name of transition, as already stated, was first given by Werner, to designate a mineral character, inter- mediate between the highly crystalline or metamorphic state and that of an ordinary fossiliferous rock. But the term acquired also from the first a chronological import, because it had been appropriated to sedimentary formations, which, in the Hartz and other parts of Germany, were more ancient than the oldest of the secondary series, and were characterized by peculiar fossil zoophytes and shells. When, therefore, geologists found in other districts stratified rocks occupying the same position, and inclosing similar fossils, they gave to them also the name of transition, according to rules which will be explained in the next chapter; yet, in many cases, such rocks were found not to exhibit the same mineral texture which Werner had called transition. On the contrary, many of them were not more crystalline than different members of the secondary class; while, on the other hand, these last were sometimes found to assume a semi- Cu. VIIL] CHANGES OF NOMENCLATURE. 93 crystalline and almost metamorphic aspect, and thus, on lithological grounds, to deserve equally the name of transition. So remarkably was this the case in the Swiss Alps, that certain rocks, which had for years been regarded by some of the most skilful disciples of Werner to be tran- sition, were at last acknowledged, when their relative position and fossils were better understood, to belong to the newest of the secondary groups ; nay, some of them have actually been discovered to be members of the lower tertiary series! If, under such circumstances, the name of transition was retained, it is clear that it ought to have been applied without refer- ence to the age of strata, and simply as expressive of a mineral peculiarity. The continued appropriation of the term to formations of a given date, in- duced geologists to go on believing that the ancient strata so designated bore a less resemblance to the secondary than is really the case, and to imagine that these last never pass, as they frequently do, into metamor- phic rocks. The poet Waller, when lamenting over the antiquated style of Chaucer, complains that— We write in sand, our language grows, And, like the tide, our work o’erflows. But the reverse is true in geology ; for here it is our work which contin- ually outgrows the language. The tide of observation advances with such speed that improvements in theory outrun the changes of nomenclature ; and the attempt to inculcate new truths by words invented to express a different or opposite opinion, tends constantly, by the force of association to perpetuate error; so that dogmas renounced by the reason still retain a strong hold upon the imagination. In order to reconcile the old chronological views with the new doctrine of the igneous origin of granite, the following hypothesis was substituted for that of the Neptunists. Instead of beginning with an aqueous men- struum or chaotic fluid, the materials of the present crust of the earth were supposed to have been at first in a state of igneous fusion, until part of the heat having been diffused into surrounding space, the surface of the fluid consolidated, and formed a crust of granite. This covering of crys- talline stone, which afterwards grew thicker and thicker as it cooled, was so hot, at first, that no water could exist upon it; but as the refrigeration proceeded, the aqueous vapor in the atmosphere was condensed, and, fall- ing in rain, gave rise to the first thermal ocean. So high was the tem- perature of this boiling sea, that no aquatic beings could inhabit its waters, and its deposits were not only devoid. of fossils, but, like those of some hot springs, were highly crystalline. Hence the origin of the primary or crystalline strata,—gneiss, mica-schist, and the rest. Afterwards, when the granitic crust had been partially broken up, land and mountains began to rise above the waters, and rains and torrents to grind down rock, so that sediment was spread over the bottom of the seas. Yet the heat still remaining in the solid supporting substances was sufficient to increase the chemical action exerted by the water, al- though not so intense as to prevent the introduction and increase of some 94 CHRONOLOGICAL ARRANGEMENT {Cs. VII. 3s living beings. During this state of things some of the residuary mineral ingredients of the primeval ocean were precipitated, and formed deposits (the transition strata of Werner), half chemical and half mechanical, and containing a few fossils. By this new theory, which was in part a revival of the doctrine of Leibnitz, published in 1680, on the igneous origin of the planet, the old ideas respecting the priority of all crystalline rocks to the creation of or- ganic beings, were still preserved ; and the mistaken notion that all the semi-crystalline and partially fossiliferous racks belonged to one period, while all the earthy and uncrystalline formations origimated at a subse- quent epoch, was also perpetuated. It may or may not be true, as the great Leibnitz imagined, that the whole planet was once in a state of liquefaction by heat; but there are cer- tainly no geological proofs that the granite which constitutes the founda- tion of so much of the earth’s crust was ever at once in a state of universal fusion. On the contrary, all our evidence tends to show that the formation of granite, like the deposition of the stratified rocks, has been successive, and that different portions of granite have been in a melted state at dis- tinct and often distant periods. One mass was solid, and had been frac- tured, before another body of granitic matter was injected into it, or through it, in the form of veins. Some granites are more ancient than any known fossiliferous rocks; others are of secondary ; and some, such as that of Mont Blanc and part of the central axis of the Alps, of tertiary origin. In short, the universal fluidity of the crystalline foundations of the earth’s crust, can only be understood in the same sense as the universality of the ancient ocean. All the land has been under water, but not all at one time ; so all the subterranean unstratified rocks to which man ean obtain access have been melted, but not simultaneously. In the present work the four great classes of rocks, the aqueous, plutonic, volcanic, and metamorphic, will form four parallel, or nearly parallel, col- umns in one chronological table. They will be considered as four sets of monuments relating to four contemporaneous, or nearly contemporaneous, series of events. I shall endeavor, in a subsequent chapter on the plutonic rocks, to explain the manner in which certain masses belonging to each of the four classes of rocks may have originated simultaneously at every geological period, and how the earth’s crust may have been continually modelled, above and below, by aqueous and igneous causes, from times indefinitely remote. In the same manner as aqueous and fossiliferous strata are now formed in certain seas or lakes, while in other places vol- canic rocks break out at the surface, and are connected with reservoirs of melted matter at vast depths in the bowels of the earth,—so, at every era of the past, fossiliferous deposits and superficial igneous rocks were in progress contemporaneously with others of subterranean and plutonic ori- gin, and some sedimentary strata were exposed to heat and made to as- sume a crystalline or metamorphic structure. It can by no means be taken for granted, that during all these changes the solid crust of the earth has been increasing in thickness. It has been Cx. VIII] OF ROCKS IN GENERAL. 95 shown, that so far as aqueous action is concerned, the gain by fresh deposits, and the loss by denudation, must at each period have been equal (see above, p- 68): and in like manner, in the inferior portion of the earth’s crust, the acquisition of new crystalline rocks, at each successive era, may merely have counterbalanced the loss sustained by the melting of materials previously consolidated. As to the relative antiquity of the crystalline foundations of the earth’s crust, when compared to the fossiliferous and volcanic rocks which they support, I have already stated, in the first chapter, that to pro- nounce an opinion on this matter is as difficult as at once to decide which of the two, whether the foundations or superstructure of an ancient city built on wooden piles, may be the oldest. We have seen that, to answer this question, we must first be prepared to say whether the work of decay and restoration had gone on most rapidly above or below, whether the average duration of the piles has exceeded that of the stone buildings, or the contrary. So also in regard to the relative age of the superior and inferior portions of the earth’s crust; we cannot hazard even a conjecture on this point, un- til we know whether, upon an average, the power of water above, or that of heat below, is most efficacious in giving new forms to solid matter. After the observations which have now been made, the reader will per- ceive that the term primary must either be entirely renounced, or, if re- tained, must be differently defined, and not made to designate a set of crystalline rocks, some of which are already ascertained to be newer than all the secondary formations. In this work I shall follow most nearly the method proposed by Mr. Boué, who has called all fossiliferous rocks older than the secondary by the name of primary. To prevent con- fusion, I shall sometimes speak of these last as the primary fossiliferous formations, because the word primary has hitherto been most generally connected with the idea of a non-fossiliferous rock. Some geologists, to avoid misapprehension, have introduced the term Paleozoic for primary, from raroiov, “ ancient,” and Zaov, “an organic being,” still retaining the terms secondary and tertiary; Mr. Phillips, for the sake of uniformity, has proposed Mesozoic, for secondary, from mecog, “ middle,” &c.; and Caino- zoic, for tertiary, from xcvos, “recent,” &c.; but the terms primary, sec- ondary, and tertiary are synonymous, and have the claim of priority in their favor. If we can prove any plutonic, volcanic, or metamorphic rocks to be older than the secondary formations, such rocks will also be primary, ac- cording to this system. Mr. Boué, having with propriety excluded the metamorphic rocks, as a class, from the primary formations, proposed to call them all “ crystalline schists.” As there are secondary fossiliferous strata, so we shall find that there are plutonic, volcanic, and metamorphic rocks of contemporaneous origin, which I shall also term secondary. In the next chapter it will be shown that the strata above the chalk have been called tertiary. If, therefore, we discover any volcanic, plutonic, or metamorphic rocks, which have originated since the deposition of the chalk, these also will rank as tertiary formations. 96 TESTS OF THE DIFFERENT AGES [Cu. IX. It may perhaps be suggested that some metamorphic strata, and some granites, may be anterior in date to the oldest of the primary fossilifer- ous rocks. This opinion is doubtless true, and will be discussed in future chapters; but I may here observe, that when we arrange the four classes of rocks in four parallel columns in one table of chronology, it is by no means assumed that these columns are all of equal length; one may begin at an earlier period than the rest, and another may come down to a later point of time. In the small part of the globe hitherto examined, it is hardly to be expected that we should have discovered either the oldest or the newest members of each of the four classes of rocks. Thus, if there be primary, secondary, and tertiary rocks of the aqueous or fos- siliferous class, and in like manner primary, secondary, and tertiary hypo- gene formations, we may not be yet acquainted with the most ancient of the primary fossiliferous beds, or with the newest of the hypogene. CHAPTER IX. ON THE DIFFERENT AGES OF THE AQUEOUS ROCKS. On the three principal tests of relative age—Superposition, mineral character, and fossils—Change of mineral character and fossils in the same continuous formation—Proofs that distinct species of animals and plants have lived at suc- cessive periods—Distinct provinces of indigenous species—Great extent of single proyinces—Similar laws prevailed at successive geological periods— Relative importance of mineral and palzontological characters—Test of age by included fragments—Frequent absence of strata of intervening periods—Prin- cipal groups of strata in western Europe. In the last chapter I spoke generally of the chronological relations of the four great classes of rocks, and I shall now treat of the aqueous rocks in particular, or of the successive periods at which the different fossilif- erous formations have been deposited. There are three principal tests by which we determine the age of a given set of strata; first, superposition; secondly, mineral character ; and, thirdly, organic remains. Some aid can occasionally be derived from a fourth kind of proof, namely, the fact of one deposit including in it fragments of a pre-existing rock, by which the relative ages of the two may, even in the absence of all other evidence, be determined. Superposition—The first and principal test of the age of one aqueous deposit, as compared to another, is relative position. It has been already stated, that where strata are horizontal, the bed which lies uppermost is the newest of the whole, and that which lies at the bottom the most ancient. So, of a series of sedimentary formations, they are like vol- umes of history, in which each writer has recorded the annals of his own Cu. IX.] OF AQUEOUS ROCKS. 97 times, and then laid down the book, with the last written page upper- most, upon the volume in which the events of the era immediately pre- ceding were commemorated. In this manner a lofty pile of chronicles is at length accumulated ; and they are so arranged as to indicate, by their position alone, the order in which the events recorded in them have occurred. In regard to the crust of the earth, however, there are some regions where, as the student has already been informed, the beds have been dis- turbed, and sometimes extensively thrown over and turned upside down. (See pp. 58, 59.) But an experienced geologist can rarely be deceived by these exceptional cases. When he finds that the strata are fractured, curved, inclined, or vertical, he knows that the original order of superpo- sition must be doubtful, and he then endeavors to find sections in some neighboring district where the strata are horizontal, or only slightly in- clined. Here the true order of sequence of the entire series of deposits being ascertained, a key is furnished for settling the chronology of those strata where the displacement is extreme. Mineral character —The same rocks may often be observed to retain for miles, or even hundreds of miles, the same mineral peculiarities, if we fol- low the planes of stratification, or trace the beds, if they be undisturbed, in a horizontal direction. But if we pursue them vertically, or in any direc- tion transverse to the planes of stratification, this uniformity ceases almost immediately. In that case we can scarcely ever penetrate a stratified mass for a few hundred yards without beholding a succession of extremely dis- similar rocks, some of fine, others of coarse grain, some of mechanical, others of chemical origin; some calcareous, others argillaceous, and others silice- ous. These phenomena lead to the conclusion, that rivers and currents. haye dispersed the same sediment over wide areas at one period, but at: successive periods haye been charged, in the same region, with very differ- ent kinds of matter. The first observers were so astonished at the vast. spaces over which they were able to follow the same homogeneous rocks. in a horizontal direction, that they came hastily to the opinion, that the- whole globe had been enyironed by a succession of distinct aqueous forma-- tions, disposed round the nucleus of the planet, like the concentri¢ coats of. an onion, But although, in fact, some formations may be continuous over districts as large as half of Europe, or‘even more, yet most of them either. terminate wholly within narrower limits, or soon change their lithological, character. Sometimes they thin out gradually, as if the supply of sedi- ment had failed in that direction, or they come abruptly to an end, as if we had arrived at the borders of the ancient sea or lake which served as. their receptacle. It no less frequently happens that they vary in mineral aspect and composition, as we pursue them horizontally. For example, we trace a limestone for a hundred miles, until it becomes more arena-- ceous, and finally passes into sand, or sandstone. We may then follow this sandstone, already proved by its continuity to be of the same age, through- out another district a hundred milés or more ia length. Organic remains.—This character must be used as a criterion of. the: hy e 98 TESTS OF THE DIFFERENT AGES Ga, I age of a formation, or of the contemporaneous origin of two deposits in distant places, under very much the same restrictions as the test of min- eral composition. First, the same fossils may be traced over wide regions, if we examine strata in the direction of their planes, although by no means for indefi- nite distances. Secondly, while the same fossils prevail in a particular set of strata for hundreds of miles in a horizontal direction, we seldom meet with the same remains for many fathoms, and very rarely for several hundred yards, in a vertical line, or a line transverse to the strata. This fact has now been verified in almost all parts of the globe, and has led to a con- viction, that at successive periods of the past, the same area of land and water has been inhabited by species of animals and plants even more distinct than those which now people the antipodes, or which now co- exist in the arctic, temperate, and tropical zones. It appears, that from the remotest periods there has been ever a coming in of new organic forms, and an extinction of those which pre-existed on the earth; some species having endured for a longer, others for a shorter, time; while none have ever reappeared after once dying out. The law which has governed the creation and extinction of species seems to be expressed in the verse of the poet,— Natura il fece, e poi ruppe la stampa. ARIOSTO. Nature made him, and then broke the die. And this circumstance it is which confers on fossils their highest value as chronological tests, giving to each of them, in the eyes of the geologist, that authority which belongs to contemporary medals in history. The same cannot be said of each peculiar variety of rock ; for some ‘of these, as red marl and red sandstone, for example, may occur at once at the top, bottom, and middle of the entire sedimentary series; exhib- iting in each position so perfect an identity of mineral aspect as to be undistinguishable. Such exact repetitions, however, of the same mix- tures of sediment have not often been produced, at distant periods, in precisely the same parts of the globe; and even where this has hap- pened, we are seldom in any danger of confounding together the monu- ments of remote eras, when we have studied their imbedded fossils and their relative position. It was remarked that the same species of organic remains cannot be traced horizontally, or in the direction of the planes of stratification for indefinite distances. This might have been expected from analogy; for when we inquire into the present distribution of living beings, we find that the habitable surface of the sea and land may be divided into a ‘considerable number of distinct provinces, each peopled by a peculiar ‘assemblage of animals and plants. In the Principles of Geology, I have ‘endeavored to point out the extent and probable origin of these separate ‘divisions ; and it was shown that climate is only one of many causes on alae Cz. IX.] OF AQUEOUS ROCKS. 99 which they depend, and that difference of longitude as well as latitude is generally accompanied by a dissimilarity of indigenous species. As different seas, therefore, and lakes are inhabited at the same period, by different aquatic animals and plants, and as the lands adjoining these may be peopled by distinct terrestrial species, it follows that distinct fossils will be imbedded in contemporaneous deposits. If it were otherwise—if the same species abounded in every climate, or in every part of the globe where, so far as we can discover, a corresponding temperature and other conditions favorable to their existence are found—the identification of mineral masses of the same age, by means of their included organic contents, would be a matter of still greater certainty. Nevertheless, the extent of some single zoological provinces, es- pecially those of marine animals, is very great; and our geological researches have proved that the same laws prevailed at remote periods ; for the fossils are often identical throughout wide spaces, and in de- tached deposits, consisting of rocks varying entirely in their mineral nature. The doctrine here laid down will be more readily understood, if we reflect on what is now going on in the Mediterranean. That entire sea may be considered as one zoological province; for, although certain species of testacea and zoophytes may be very local, and each region has probably some species peculiar to it, still a considerable number are com- mon to the whole Mediterranean. — If, therefore, at some future period, the bed of this inland sea shou!d be converted into land, the geologist might be enabled, by reference to organic remains, to prove the contem- poraneous origin of various mineral masses scattered over a space equal in area to half of Europe. Deposits, for example, are well known to be now in progress in this sea in the deltas of the Po, Rhone, Nile, and other rivers, which differ as greatly from each other in the nature of their sediment as does the composition of the mountains which they drain. There are also other quarters of the Mediterranean, as off the coast of Campania, or near the base of Etna, in Sicily, or in the Grecian Archipelago, where another class of rocks is now forming; where showers of volcanic ashes occa- sionally fall into the sea, and streams of lava overflow its bottom ; and where, in the intervals between volcanic eruptions, beds of sand and clay are frequently derived from the waste of cliffs, or the turbid waters of rivers. Limestones, moreover, such as the Italian travertins, are here and there precipitated from the waters of mineral springs, some of which rise up from the bottom of the sea. {In all these detached formations, so diversified in their lithological characters, the remains of the same shells, corals, crustacea, and fish are becoming inclosed ; or, at least, a sufficient number must be common to the different localities to enable the zoologist to refer them all to one contemporaneous assemblage of species. There are, however, certain combinations of geographical circum- stances which cause distinct provinces of animals and plants to be sepa- 100 TESTS OF THE DIFFERENT AGES [Cu. IX, rated from each other by very narrow limits; and hence it must happen, that strata will be sometimes formed in contiguous regions, differmg widely both in mineral contents and organic remains. Thus, for exam- ple, the testacea, zoophytes, and fish of the Red Sea are, as a group, ex- tremely distinct from those inhabiting the adjoining parts of the Mediter- ranean, although the two seas are separated only by the narrow isthmus of Suez. Of the bivalve shells, according to Philippi, not more than a fifth are common to the Red Sea and the sea around Sicily, while the proportion of univalves (or Gasteropoda) is still smaller, not exceeding eighteen in a hundred. Calcareous formations have accumulated on a great scale in the Red Sea in modern times, and fossil shells of existing species are well preserved therein; and we know that at the mouth of the Nile large deposits of mud are amassed, including the remains of Mediterranean species. It follows, therefore, that if at some future pe- riod the bed of the Red Sea should be laid dry, the geologist might ex- perience great difficulties in endeavoring to ascertain the relative age of these formations, which, although dissimilar both in organic and mineral characters, were of synchronous origin. But, on the other hand, we must not forget that the northwestern shores of the Arabian Gulf, the plains of Egypt, and the isthmus of Suez, are all parts of one province of terrestrial species. Small streams, therefore, occasional land-floods, and those winds which drift clouds of sand along the deserts, might carry down into the Red Sea the same shells of fluviatile and land testacea which the Nile is sweeping into its delta, together with some remains of terrestrial plants and the bones of quadrupeds, whereby the groups of strata, before alluded to, might, not- withstanding the discrepancy of their mineral composition and marine organic fossils, be shown to have belonged to the same epoch. Yet while rivers may thus carry down the same fluviatile and ter- restrial spoils into two or more seas inhabited by different marine species, it will much more frequently happen, that the coexistence of terrestrial species of distinct zoological and botanical provinces will be proved by the identity of the marine beings which inhabited the intervening space. Thus, for example, the land quadrupeds and shells of the south of Eu- rope, north of Africa, and northwest of Asia, differ considerably, yet their remains are all washed down by rivers flowing from these three countries into the Mediterranean. In some parts of the globe, at the present period, the line of demarea- tion between distinct provinces of animals and plants is not very strongly marked, especially where the change is determined by temperature, as it is in seas extending from the temperate to the tropical zone, or from the temperate to the arctic regions. Here a gradual passage takes place from one set of species to another. In like manner the geologist, in studying particular formations of remote periods, has sometimes been able to trace the gradation from one ancient province to another, by ob- serving carefully the fossils of all the intermediate places. His success in thus acquiring a knowledge of the zoological or botanical geography Cx. IX] OF AQUEOUS ROCKS. 101 of very distant eras has been mainly owing to this circumstance, that the mineral character has no tendency to be affected by climate. A large river may convey yellow or red mud into some part of the ocean, where it may be dispersed by a current over an area several hundred leagues in length, so as to pass from the tropics into the temperate zone. If the bottom of the sea be afterwards upraised, the organic remains imbedded in such yellow or red strata may indicate the different animals er plants which once inhabited at the same time the temperate and equatorial regions. It may be true, as a general rule, that groups of the same species of animals and plants may extend over wider areas than deposits of homo- geneous composition ; and if so, palzeontological characters will be of more importance in geological classification than the test of mineral com- position ; but it is idle to discuss, the relative value of these tests, as the aid of both is indispensable, and it fortunately happens, that where the one criterion fails, we can often avail ourselves of the other. Test by included fragments of older rocks.—It was stated, that inde- pendent proof may sometimes be obtained of the relative date of two formations, by fragments of an older rock being included in a newer one. This evidence may sometimes be of great use, where a geologist is at a loss to determine the relative age of two formations from want of clear sections exhibiting their true order of position, or because the strata of each group are vertical. In such cases we sometimes discover that the more modern rock has been in part derived from the degradation of the older. Thus, for example, we may find chalk with flints in one part of a country; and, in another, a distinct formation, consisting of alternations of clay, sand, and pebbles. If some of these pebbles consist of similar flint, including fossil shells, sponges, and foraminiferze, of the same species as those in the chalk, we may confidently infer that the chalk is the oldest of the two formations. Chronological groups——The number of groups into which the fossil- iferous strata may be separated are more or less numerous, according to the views of classification which different geologists entertain ; but when we have adopted a certain system of arrangement, we immediately find that a few only of the entire series of groups occur one upon the other in any single section or district. The thinning out of individual strata was before described (p. 16). " RAOawn we But let the annexed diagram represent seven fossiliferous groups, instead of as many strata. It will then be seen that in the middle all the super- imposed formations are present; but in consequence of some of them 102 CHRONOLOGICAL ARRANGEMENT [Ox LXs. thinning out, No. 2 and No. 5 are absent at one extremity of the sec- tion, and No. 4 at the other. In the annexed diagram, fig. 105, a real section of the geological formations in the neighborhood of Bristol and the Mendip Hills, is pre- sented to the reader as laid down on a true scale by Professor Ramsay, where the newer groups 1, 2, 3, 4 rest unconformably on the formations Fig. 105. 8 Dundry Hill. N SS SS = ——— Section South of Bristol. A.C. Ramsay. Length of section 4 miles. a, 6. Level of the sea, 1. Inferior oolite. 5. Coal measure. 2, Lias. 6. Carboniferous limestone. 3. New red sandstone. 7. Old red sandstone. 4, Magnesian conglomerate. 5 and 6, Here at the southern end of the line of section we meet with the beds No. 3 (the New Red Sandstone) resting immediately on No. 6, while farther north, as at Dundry Hill, we behold six groups superim- posed one upon the other, comprising all the strata from the inferior oolite to the coal and carboniferous limestone. The limited extension of the groups 1 and 2 is owing to denudation, as these formations end ab- ruptly, and have left outlying patches to attest the fact of their haying originally covered a much wider area. In many instances, however, the entire absence of one or more forma- tions of intervening periods between two groups, such as 3 and 5 in the same section, arises, not from the destruction of what once existed, but because no strata of an intermediate age were ever deposited on the in- ferior rock. They were not formed at that place, either because the region was dry land during the interval, or because it was part of a sea or lake to which no sediment was carried. In order, therefore, to establish a chronological succession of fossilifer- ous groups, a geologist must begin with a single section, in which sey- eral sets of strata lie one upon the other. He must then trace these formations, by attention to their mineral character and fossils, continu- ously, as far as possible, from the starting point. As often as he meets with new groups, he must ascertain by superposition their age relatively to those first examined, and thus learn how to intercalate them in a tab- ular arrangement of the whole. By this means the German, French, and English geologists have de- termined the succession of strata throughout a great part of Europe, and have adopted pretty generally the following groups, almost all of which have their representatives in the British Islands. Ca. IX.] OF AQUEOUS ROCKS. 103 Groups of Fossiliferous Strata observed in Western Hurope, arranged in what is termed a descending Series, or beginning with the newest. (See a more detailed Tabular view, pp. 104-108.) _ . Post-Pliocene, including those of the Recent, or human period. 2. Newer Pliocene, or Pleistocene. 3. Older Pliocene. Tertiary, Supracretaceous,* or 4, Miocene. Cainozoic. + 5. Eocene. . : 6. Chalk. 47. Greensand and Wealden. 8. Upper Oolite, including the Purbeck. 9. Middle Oolite. Secondary, or Mesozoic. 10. Lower Oolite. 11. Lias. 12. Trias. 13. Permian. 14. Coal. 15. Old Red sandstone, or Devonian. 16. Upper Silurian. Primary fossiliferous, or palee 17. Lower Silurian. ZOIC. 18. Cambrian and older fossiliferous strata. It is not pretended that the three principal sections in the above table, ealled primary, secondary, and tertiary, are of equivalent importance, or that the eighteen subordinate groups comprise monuments relating to equal portions of past time, or of the earth’s history. But we can assert that they each relate to successive periods, during which certain animals and plants, for the most part peculiar to their respective eras, have flour- ished, and during which different kinds of sediment were deposited in the space now occupied by Europe. If we were disposed, on paleontological grounds,f to divide the entire fossiliferous series into a few groups less numerous than those in the above table, and more nearly co-ordinate in value than the sections called pri- mary, secondary, and tertiary, we might, perhaps, adopt the six groups or periods given in the next table. At the same time, I may observe, that, in the present state of the science, when we have not yet compared the evidence derivable from all classes of fossils, not even those most generally distributed, such as shells, corals, and fish, such generalizations are premature, and can only be regarded as conjectural or provisional schemes for the founding of large natural groups. * For tertiary, Sir H. De la Beche has used the term “ supracretaceous,” a name implying that the strata so called are superior in position to the chalk. + For an explanation of Cainozoic, see p. 95. $ Palzontology is the science which treats of fossil remains, both animal and vegetable. tym, madawos, palaios, ancient, ovta, onta, beings, and Aoyos, logos, a discourse. 104 TABULAR VIEW OF FOSSILIFEROUS STRATA. [Ca. IX Fossiliferous Strata of Western Europe divided into Six Groups. u “Oe sf ot from the Post-Pliocene to the Eocene inclusive. 2. Cretaceous - - from the Maestricht Chalk to the Wealden inclusive. 8. Oolitic - . - from the Purbeck to the Lias inclusive. One including the Keuper, Muschelkalk, and Bunter Sand- 4. Triassic - =} stein of the Gosia i 5. Permian, Carbonifer- } including Magnesian Limestone (Zechstein), Coal, Moun- ous, and Devonian tain Limestone, and Old Red Sandstone. 6. Silurian and Cam- } from the Upper Silurian to the oldest fossiliferous rocks brian - - - inclusive. But the following more detailed list of fossiliferous strata, divided into thirty-five sections, will be required by the reader when he is studying our descriptions of the sedimentary formations given in the next 18 chapters. TAB U LA Re Vole Ww OF THE FOSSILIFEROUS STRATA, Showing the Order of Superposition or Chronological Succession of the principal Groups. British Examples, Foreign Equivalents and Synonyms, I. TERRAINS CONTEMPORAINES, ET QUATERNAIRES, Periods and Groups. I. POST-TERTIARY. A, POST-PLIOCENE. 1. RECENT. 2. POST-PLIOCENE. I. TERTIARY. B. PLIOCENE. 3. NEWER PLIOCENE, or Pleistocene. Peat of Great Britain and Ireland, with human remains. (Princi- ples of Geology, ch. 45.) Alluvial plains of the Thames, Mersey, and Rother, with buried ships, p. 120, and Principles, ch, 48. Ancient raised beach of Brighton. b. fig. 331, p. 287. Alluvyium, gravel, brick-earth, &c. with fossil shells of living species, but sometimes locally extinct, and with bones of Jand animals, partly of extinct spe- cies ; no human remains, Glacial drift or boulder-formation of Norfolk, p. 132, of the Clyde in Scotland, p. 130, of North Wales, p. 136. Norwich Crag, p. 154 —Cave-deposits of Kirk- dale, &c., with bones of extinct and living quadrupeds, p. 160, Part of the Terrain quaternaire of French authors. Modern part of deltas of Rhine, Nile, Ganges, Mississippi, &c. Modern part of coral-reefs of Red Sea and Pacific. Marine strata inclosing temple of Serapis at Puzzuoli. Principles, ch. 29. Freshwater strata inclosing Tem- ple in Cashmere. Jbid. 9th ed. p. 762. Part of Terrain quaternaire of French authors. Volcanic tuff of Ischia; with liv- ing species of marine shells and without human remains or works of art, p. 118. Loess of the Rhine, with recent freshwater shells, and mam- moth bones, p. 121. Newer part of boulder-formation in Sweden, p. 129, Bluffs of Mississippi, p. 121. II, TERRAINS TERTIAIRES. Terrain quaternaire, diluvyium. Terrains tertiaires supérieurs, p. 139. Glacial drift of Northern Europe, p. 128; and of Northern United States, p. 139; and Alpine er- ratics, p. 148. : Limestone of Girgenti, p. 159. Australian cave-breccias, p. 161. Cu. IX] Periods and Groups. British Examples 4. OLDER Red Crag of Suffolk, pp. 168-170. PLIOCENE. Gera line crag of Suffolk, pp. 168- ii. C. MIOCENE. Marine strata of this age wanting in the British Isles. 5. -MIOCENE. Leaf- sae of Mull in the Hebrides ? Liznite of Antrim ?, p. 180. D. EOCENE. 6. UPPER EOCENE (Gower Miocene of many authors). Hempstead beds, near erent Isle of Wight, p. 192 1. Bembridge, or Binstead Beds, Isle of Wight, p. 2. Osborne or St. Helen’ 8 Series, . 210. 3. Headon Series. Ibid. 4, Headon Hill Sands, and Bar- ton Clay, p. 212. 5. Bagshot and Bracklesham Beds, p. 213. 6. Wanting? See p. 222, 7. MIDDLE EOCENE. f 1. London Clay and Bognor Beds, . 216. 2. Plastic and Mottled Clays and Sands, and Woolwich Beds, p 219. 3. “Thanet Sands, p. 221. 8. LOWER EOCENE. TL SECONDARY. £. CRETACEOUS. § Upper negream 9- Tes ee sCHT Wanting in England. 10. UPPER White Chalk with Flints, of North WHITE CHALE. and South Downs, p. 340, Chalk erty Flints, and Chalk Marl, Chalk Marl. Ibid. LOWER WHITE CHALK. 11. | | : TABULAR VIEW OF FOSSILIFEROUS STRATA. Kleyn Spawen or Limburg beds, Belgium—Rupelian and Tong- rian systems of Dumont, p. 188. 105 Foreign Equivalents and Synonyms. [ Subapennine strata, p. 173. Hills of Rome, Monte Mario, &c. p. 175, and p. 531. SUewerD and Normandy crag, p. 17 Aralo-Caspian deposits, p. 175. C. TERRAINS TERTIAIRES MOY- ENS, PARTIE SUPERIEURE; OR FALUNS, Falunien supérieur, D’Orbigny. Faluns of Touraine, p. 175. Part of Bourdeaux beds, p. 178. Bolten bere strata in Belgium, Pp. Part of Vienna basin, p. 179. ona of Molasse, Switzerland, p. 1 Sands of James River, and Rich- mi, Virginia, United States, p. 181. Lower part of Terrain Tertiaire Moyen. Calcaire Lacustre Supérieur and Grés de Fontainebleau, p. 194. Part of the Lacustrine strata of Auvergne, p. 194. Mayence basin, p. 190. Part of brown-coal of Germany, pp. 191, 540. Hermsdorf tile- -clay near Berlin, p. 189. 1. Gypseous Series of Montmartre, owe Calcaire lacustre supérieur, 223. 2 k 3. Calcaire Siliceux, p. 225. 2 & 3. Grés de Beauchamp, or Sables Moyens, p. 226. Laecken beds, Belgium 4&5. ‘ignice and Middle Calcaire Grossier, p. 226. 5. Bruxellien, or Brussels beds of Dumont. 5. Lower Calcaire Grossier, or Glauconie Grossiére, p. 228. 5. Claiborne beds, United States, p. 232. 5 & 6. Nummulitic formation of Europe, Asia, &c., p. 229. 6. Soissonnais Sands, or Lits Co- quilliers, p. 228, 1. Wanting in Paris basin, occurs at Cassel, in French Flanders. 2. po Plastique et Lignite, p. Alabama, BE Tine Landenian of Belgium in part?, p. 235. III. TERRAINS SECONDAIRES, £, TERRAINS CRETACEES, { 9. Danien of D’Orbigny. gelesire pisolitique, near Paris, 5. p. 235. Maestricht Beds, p. 237. Coralline Limestone of Faxoe in Denmark, p. 238. 10. Senonien, D’Orbigny. Craie blanche avec silex. Obere Kreide of the Germans. Upper Quadersandstein? of the same. La Scaglia of the Italians. Calcaire 4 hippurites, Pyrenees. | Turonien, D’Orbigny, or, Craie tufeau of Touraine. Craie argileuse of some French writers. Upper Planerkalk of Saxony. { Loose sand with bright green (eres vert supérieur, 12. UPPER GREENSAND. ibid. lL Wight, grains, p. 250. Firestone Pof Merstham, Surrey, Marly Stone with. Chert, Isle of Glauconie crayeuse, Craie chloritée. Cenomanien, D’Orbigny. Lower Quadersandstein of the Germans. 106 Periods and Groups TABULAR VIEW OF FOSSILIFEROUS STRATA. [Ca. TX. British Examples, Foreign Equivalents and Synonyms, Dark Blue Marl, Kent, p. 250. Grés vert supérieur on sera Folkestone Marl or Clay. Glauconie crayeuse party ) Blackdown Beds, green sand and 1 Albien, D’ Orbigny. chert, Devonshire, p. 251. | Lower Planer of Saxony §§ Lower Carraczous, or Neocomray. 13. GAULT. 14. LOWER GREENSAND. 15. WEALDEN (Weald Clay and Hastings Sand). F. OOLITE. § Upper Oorite. 16. PURBECK BEDS. 17. PORTLAND BEDS. 18. KIMMERIDGE CLAY. §$ Mmppre Oo ite. 19. CORAL-RAG. 20. OXFORD CLAY. §$$ Lower Oo ITE. 21. GREAT or BATH OOLITE. INFERIOR OOLITE. 22. G. LIAS. 23. LIAS. H. TRIAS. (Upper N 24. UPPER TRIAS. 25. MIDDLE TRIAS or Muschelkalk. 26. LOWER TRIAS. Sand with green matter, Weald of Kent and Sussex, p. 257. Limestone (Kentish Rag,) p. 257. Sands and clay with calcareous concretions and chert. Atherfield, Isle of HO OS ES p. 257. { Speeton Clay, Yorkshi Yorkshire. l Grés vert inférieur. Néocomien supérieur. apne D’Orbign Hils- cone lomerd of omic ra Wel cunanye Hils-thon of Brunswicl Brunswick. Clay with occasional bands of limestone.—Weald of Kent, Sur- rey, and Sussex, p. 260. Sand’ with calcareous grit and Cuckfield, { Formation Waldienne. i Néocomien inférieur. clay, — Hastings | Sussex, p. 262. : F. TERRAINS JURASSIQUES, in part. Serpulitenkalk of Dunker, and Upper, Middle, and Lower Pur- associated beds of the North beck, Dorsetshire and Wilts, pp. 293-296. German Walderformation. § Horland stone and Portlandsand, § G,oupe Portlandien of Beudant p. ) * Caleaire a gryphées virgules, of Thirria. Argiles de Honfleur, E. de Beau- mont et Dufresnoy. § oy of Kimmeridge, Dorset- shire, p. Groupe corallien de Beudant. Corallien, D’?Orbigny. Calcaire 4 Nérinnées of Thur- rt mann and Thirria. 1. Oxfordien mann. 2. Oxfordien inférieur, or Callos vien, D’Orbigny. Caleareous grit. Coral-rag or oolitic with corals, Oxfordshire, p. 302. F Dark blue clay, Oxfordshire Kimmeridgien, D’Orbigny. limestone supérieur, Thur- and Midland counties, p. 304. 2. Calcareous concretionary lime- stone with shells, called Kel- loway Rock, p. 34. Bathonien of Omalius D’Halloy, Grand Oolithe. Calcaire de Caen. Wiltshire, p. 305. 2. Great Oolite and Stonesfield Slate,—Bath, Stonesfield, pp. 305-309. Fuller’s Earth, near Bath,’p. 314. Calcareous freestone, and yellow sands of Cotteswold_ Hills, Gloucestershire, p. 314. (aon Hill, 102, 314. Oolithe inférieur. Oolithe ferrugineux of Normandy. Oolithe de Bayeux. ! Bajocien of D’Orbigny. ie Cornbrash and Forest Marble, near Bristol, pp. : G. TERRAINS JURASSIQUES, in part. 1. Btage du Lias, Thirria. Toarcien D’Orbigny. 2. Lias moyen. Liasien, D’Orbigny. 3. Calcaire a gryphée arquée. Sinémurien, D’Orbigny. Coal-field near Richmond, Vir- ginia, p. 30. supérieur 2. Marl-stone, ibid. 1. Upper Lias, p. 318. 3. Lower Lias, ibid. H. Nouveau Gres RouGe. Jew Red Sandstone.) Keuper of the Germans. Marnes irisées of the French. Saliférien, D’Orbigny. au and shales of Cheshire, p. 333-336. l Bone. -bed of Axmonth, Devon. p. Muschelkalk of the Germans.’ =e Calcaire conch lien, Brongniart. | Wanting in England. Calcaire a Cératites, Cordier. l ( Conchylien, D’Orbigny (in part). ; Red and white sandstone of Lan- ; Bunter-Sandstein of the Germans, Saliferous and Gypseous sand- [3 l cashire and Cheshire, pp. 336, 4 Grés bigarré of the French. 16 Conchylien, D’Orbigny (in part). Cx. IX] Periods and Groups. British Examples, IV. PRIMARY. I PERMIAN, orn MaGnrstaAN LIMEsTONE. (Lower New Red.) 1. Concretionary limestone of Durham and Yorkshire, p. 351. 2. Brecciated limestone, ibid. 27. PERMIAN, 3. Fossiliferous limestone, p. 352. or 4. Compact simestone; ibid. “0. 5. Marl-Slate of Durham, p. MAGNESIAN 6. Inferior sandstones of various LIMESTONE. colors,—N. of England, p. 354. Dolomitic conglomerate,—Bris- tol, p. 354. KX. CARBONIFEROUS. 1. Coalemeasures, sandstone and shale with seams of coal,— 28. UPPER West of England and Ireland, CARBONIFEROUS. Chapters 24 and 25. : 2. Millstone Grit, pp. 358, 359. 1. Mountain or Carboniferous limestone, p. 403, et seq. 2. Lower limestone shale,—Men- 29. LOWER dips. Carboniferous slate,— CARBONIFEROUS. Treland. Carbonaceous schist with Possi- | donomya Becheri, p. 409. L. DEVONIAN, or Otp Rep SANDSTONE. Yellow sandstone of Dura Den, Fife, p. 412. White sandstone of Elgin, with Telerpeton, ibid. 30. UPPER Red sandstone and conglomerate, DEVONIAN. p. 414. Upper and middle Devonian of N. Devon, including Plymouth (limestone, pp. 420, 422. Lower Devonian of N. Devon, North Foreland, p. 424. 31. LOWER ae paving-stone, pp. 412- 415 DEVONIAN. Bituminous schists of Caithness, ! t p. 418. MM. SILURIAN. 1. Upper eudlow; p. 430. fe 2. Aymestry Limestone, p. b 32. UPPER 3, Lower Ludlow, iid.” SILURIAN. 4. Wenlock Limestone, p. 435. 5. Wenlock shale, p. 437.. 32 a. MIDDLE SILURIAN. (Beds of passage between Upper and Lower Silurian, vie oh or May Hill Sandstone, Llandeilo Flags and shale, p. 439. Bale pistes one and black slate, | (' fF TABULAR VIEW OF FOSSILIFEROUS STRATA. 107 Foreign Equivalents and Synonyms. IV. TERRAINS DE TRANSITION. TERRAINS PAaLEOZOIQUES. I, CALCAIRE MAGNESIEN. 1. Stinkstein of Thuringia. 2. Rauchwacke, ibid. 3. Dolomit or Upper Zechstein, 4, Zechstein, p. 350. 5. Mergel or Kanter schiefer. 6. Rothliegendes of Thuringia. Permian of Russia, p. 355. Grés des Vosges of the French (in part), K. TERRAIN HOUILLIER. ees -fields of the United States, p. 1, Calcaire carbonifére of the French. 1. BereRale or Kohlenkalk of the Germans. 1. Pentremite limestone, United States, p. 410. Kiesel-schiefer and Jtingére Grauwacke of the Germans, p. Gypseous beds and Encrinital cer one of Nova Scotia, p. 4 DL. TERRAIN DEVONIEN. VIEUX GRES ROUGE. Hussian Devonian, Upper part, p. catsill Group, United States, p. 426. Kifel Limestone, p. 424. Limestone of Villmar, &c., Nas- sau. 1. Spirifer Sandstone and Slate of Sandberger, p. 424. Older Rhenish Greywacke of Roemer, ébid. [roeeige | Devonian, Lower part, | MW. TERRAIN SILURIEN. New York division from the Up- per Pentamerus to the Niagara Group inclusive, p. 444. fitages E. to H. of Barrande, Bohemia, New York Groups from the Clin- ton to the Grey sandstone in- l clusive, p. 444. New York groups from the Hud- [ son-River beds to the Calcifer- ous sandstone inclusive, p. 444. 4 fitages and D. (Barrande), Bo- hemia. Slates of Angers, France. Primordial zone of Barrande in Bohemia, p. 450. Alum Schists of Sweden, p. 451. Potsdam Sandstone of United States and Canada, p. 451. Wisconsin and Minnesota lowest fossiliferous rocks, p. 452. #8: Sie Ae Hite Schists, 8. of Scotland. ata stall chists, 8. of Scotlan Seek: Gee Chair of Kildare, Ire- NV. CAMBRIAN 34 UPPER Ungals Flags, North Wales, p. CAMBRIAN. Stipe? Stones, Shropshire. 35. LOWER § Lowest fossiliferous rocks of CAMBRIAN. Wicklow, in Ireland, p. 449. 108 as 2. 34. 35. . LOWER . LOWER ABRIDGED TABLE OF FOSSILIFEROUS STRATA. (Ca. TX. ABRIDGED TABLE OF FOSSILIFEROUS STRATA. RECENT. POST-PLIOCENE. . NEWER PLIOCENE. . OLDER PLIOCENE. . MIOCENE. . UPPER EOCENE. . MIDDLE EOCENE. . LOWER EOCENE. . MAESTRICHT BEDS, . UPPER WHITE CHALE. . LOWER WHITE CHALK. UPPER GREENSAND. . GAULT, LOWER GREENSAND. . WEALDEN. . PURBECK BEDS. . PORTLAND STONE. . KIMMERIDGE CLAY. . CORAL RAG. . OXFORD CLAY. . GREAT or BATH OOLITE. . INFERIOR OOLITE. LIAS. UPPER TRIAS. . MIDDLE TRIAS, or MUSCHELKALKE. . LOWER TRIAS. 27. PERMIAN, or MAGNESIAN LIMESTONE, COAL-MEASURES. . CARBONIFEROUS LIMESTONE. UPPER DEVONIAN. wen {SHLURI AN. UPPER 2° SAMBRIAN, LOWER POST-TERTIARY. PLIOCENE. JURASSIC. TRIASSIC. | ; PERMIAN. CARBONIFEROUS. DEVONIAN. SILURIAN. CAMBRIAN. TERTIARY SECONDARY PRIMARY or CAINOZOIC. or MESOZOIC. OR PALEOZOIC. — NEOZOIC, PALEOZOIC. Oa. X.] PRINCIPLES OF CLASSIFICATION. 109 CHAPTER X. CLASSIFICATION OF TERTIARY FORMATIONS—POST-PLIOCENE GROUP. General principles of classification of tertiary strafta—Detached formations scat- tered over Europe—Strata of Paris and London—More modern groups— Peculiar difficulties in determining the chronology of tertiary formations—In- creasing proportion of living species of shells in strata of newer - - 1238 3086 Since the year 1830, the number of new living species obtained from different parts of the globe has been exceedingly great, supplying fresh data for comparison, and enabling the paleontologist to correct many erroneous identifications of fossil and recent forms. New spe- cies also have been collected in abundance from tertiary formations of every age, while newly discovered groups of strata have filled up gaps in the previously known series. Hence modifications and reforms have been called for in the classification first proposed. The “Eocene, Miocene, and Pliocene periods have been made to comprehend certain sets of strata of which the fossils do not always conform strictly in the propor- tion of recent to extinct species with the definitions first given by me, or which are implied in the etymology of those terms. Of these and other innovations I shall treat more fully in the 14th and 15th chapters. Post-PLIocENE ForMATIONS. I have adopted the term Post-Pliocene for those strata which are sometimes called post-tertiary or modern, and which are characterized Cu X.] POST-PLIOCENE FORMATIONS. 117 by having all the imbedded fossil shells identical with species now living, whereas even the Newer Pliocene, or newest of the tertiary deposits above alluded to, contain always some small proportion of shelis of ex- tinct species. These modern formations, thus defined, comprehend not only those strata which can be shown to have originated since the earth was inhab- ited by man, but also deposits of far greater extent and thickness, in which no signs of man or his works can be detected. In some of these, of a date long anterior to the times of history and tradition, the bones of extinct quadrupeds have been met with of species which probably never co-existed with the human race, as, for example, the mammoth, mastodon, megatherium, and others, and yet the shells are the same as those now living. That portion of the post-pliocene group which belongs to the human epoch, and which is sometimes called Recent, forms a very unimportant feature in the geological structure of the earth’s crust. I have shown, however, in “The Principles,’ where the recent changes of the earth illustrative of geology are described at length, that the deposits accumu- lated at the bottom of lakes and seas within the last 4000 or 5000 years ean neither be insignificant in volume or extent. They lie hidden, for the most part, from our sight; but we have opportunities of examining them at certain points where newly gained land in the deltas of rivers has been cut through during floods, or where coral reefs are growing rapidly, or where the bed of a sea or lake has been heaved up by sub- terranean movements and laid dry. Their age may be recognized either by our finding in them the bones of man in a fossil state, that is to say, imbedded in them by natural causes, or by their containing articles fab- ricated by the hands of man. Thus at Puzzuoli, near Naples, marine strata are seen containing frag- ments of sculpture, pottery, and the remains of buildings, together with innumerable shells retaining in part their color, and of the same species as those now inhabiting the Bay of Baie. The uppermost of these beds is about 20 feet above the level of the sea. Their emergence can be proved to have taken place since the beginning of the sixteenth cen- tury.* Now here, as in almost every instance where any alterations of level have been going on in historical periods, it is found that rocks contain- ing shells, all, or nearly all, of which still inhabit the neighboring sea, may be traced for some distance into the interior, and often to a considerable elevation above the level of the sea. Thus, in the country round Na- ples, the post-pliocene strata, consisting of clay and horizontal beds of volcanic tuff, rise at certain points to the height of 1500 feet. Although the marine shells are exclusively of living species, they are not accom- panied like those on the coast at Puzzuoli by any traces of man or his works. Had any such been discovered, it would have afforded to the antiquary and geologist matter of great surprise, since it would have * See Principles, Index, “ Serapis.” 118 POST-PLIOCENE FORMATIONS. [Cu X. shown that man was an inhabitant of that part of the globe, while the materials composing the present hills and plains of Campania were still in the progress of deposition at the bottom of the sea; whereas we know that for nearly 3000 years, or from the times of the earliest Greek colonists, no material revolution in the physical geography of that part of Italy has occurred. In Ischia, a small island near Naples, composed in like manner ot marine and voleanic formations, Dr. Philippi collected in the stratified tuff and clay ninety-two species of shells of existing species. In the centre of Ischia, the lofty hill called Epomeo, or San Nicola, is composed of greenish indurated tuff, of a prodigious thickness, interstratified in some parts with marl, and here and there with great beds of solid lava. Visconti ascertained by trigonometrical measurement that this mountain was 2605 feet above the level of the sea. Not far from its summit, at the height of about 2000 feet, as also near Moropano, a village only 100 feet lower, on the southern declivity of the mountain, I collected, in 1828, many shells of species now inhabiting the neighboring gulf. It is clear, therefore, that the great mass of Epomeo was not only raised to its present height, but was also formed beneath the waters, within the post-pliocene period. It is a fact, however, of no small interest, that the fossil shells from these modern tuffs of the volcanic regions surrounding the Bay of Baie, although none of them extinct, indicate a slight want of correspondence between the ancient fauna and that now inhabiting the Mediterranean. Philippi informs us that when he and M. Scacchi had collected ninety- nine species of them, he found that only one, Pecten medius, now living in the Red Sea, was absent from the Mediterranean. Notwithstanding this, he adds, “the condition of the sea when the tufaceous beds were deposited must have been considerably different from its present state ; for Tellina striata was then common, and is now rare; Lucina spinosa was both more abundant and grew to a larger size; Lucina fragilis, now rare, and hardly measuring 6 lines, then attained the enormous dimensions of 14 lines, and was extremely abundant; and Osirea la- mellosa, Broc., no longer met with near Naples, existed at that time, and attained a size so large that one lower valve has been known to measure 5 inches 9 lines in length, 4 inches in breadth, 14 inch in thick ness, and weighed 263 ounces.”* There are other parts of Europe where no volcanic action manif.sts itself at the surface, as at Naples, whether by the eruption of lava or by earthquakes, and yet where the land and bed of the adjoining sea are undergoing upheaval. The motion is so gradual as to be insensible te the inhabitants, being only ascertainable by careful scientific measure- ments compared after long intervals. Such an upward movement has been proved to be in progress in Norway and Sweden throughout an area about 1000 miles N. and S., and for an unknown distance E. and * Geol. Quart. Journ. vol. ii: Memoirs, p. 15. Cu. X] RECENT STRATA IN SWEDEN. dota W., the amount of elevation always increasing as we proceed towards the North Cape, where it may equal 5 feet ina century. If we could assume that there had been an average rise of 24 feet in each hundred years for the last fifty centuries, this would give an elevation of 125 feet in that period. In other words, it would follow that the shores, and a considerable area of the former bed of the Baltic and North Sea, had been uplifted vertically to that amount, and converted into land in the course of the last 5000 years. Accordingly, we find near Stockholm, in Sweden, horizontal beds of sand, loam, and marl containing the same peculiar assemblage of testacea which now live in the brackish waters of the Baltic. Mingled with these, at different depths, have been de- tected various works of art implying a rude state of civilization, and -some vessels built before the introduction of iron, the whole marine formation having been upraised, so that the upper beds are now 60 feet higher than the surface of the Baltic. In the neighborhood of these recent strata, both to the northwest and south of Stockholm, other deposits similar in mineral composition occur, which ascend to greater heights, in which precisely the same assemblage of fossil shells is met with, but without any intermixture of human bones or fabricated articles. On the opposite or western coast of Sweden, at Uddevalla, post-plio- cene strata, containing recent shells, not of that brackish water character peculiar to the Baltic, but such as now live in the northern ocean, ascend to the height of 200 feet; and beds of clay and sand of the same age attain elevations of 300 and even 700 feet in Norway, where they have been usually described as. “raised beaches.” They are, however, thick deposits of submarine origin, spreading far and wide, and filling valleys in the granite and gneiss, just as the tertiary formations, in different parts of Europe, cover or fill depressions in the older rocks. It is worthy of remark, that although the fossil fauna characterizing these upraised sands and clays consists exclusively of existing northern species of testacea, yet, according to Lovén (an able living naturalist of Norway), the species do not constitute such an assemblage as now in- habits corresponding latitudes in the German Ocean. On the contrary, they decidedly represent a more arctic fauna.* In order to find the same species flourishing in equal abundance, or in many cases to find them at all, we must go northwards to higher latitudes than Uddevalla in Sweden, or even nearer the pole than Central Norway. Judging by the uniformity of climate now prevailing from century to century, ad the insensible rate of variation in the organic world in our own times, we may presume that an extremely lengthened period was required even for so slight a modification of the molluscous fauna, as that of which the evidence is here brought to light. On the other hand, we have every reason for inferring on independent grounds (namely, the rate of upheaval of land in modern times) that the antiquity of the deposits in question must be very great. For if we assume, as before * Quart. Geol. Journ, 4 Mems. p, 48 120 RECENT AND POST-PLIOCENE FORMATIONS. [Ca X& suggested, that the mean rate of continuous vertical elevation has amounted to 23 feet in a century (and this is probably a high average), it would require 27,500 years for the sea-coast to attain the height of 700 feet, without making allowance for any pauses such as are now ex- perienced in a large part of Norway, or for any oscillations of level. In England, buried ships have been found in the ancient and now deserted channels of the Rother in Sussex, of the Mersey in Kent, and the Thames near London. Canoes and stone hatchets have been dug up, in almost all parts of the kingdom, from peat and shell-marl; but there is no evidence, as in Sweden, Italy, and many other parts of the world, of the bed of the sea, and the adjoining coast, having been up- lifted bodily to considerable heights within the human period. Recent strata have been traced along the coasts of Peru and Chili, inclosing shells in abundance, all agreeing specifically with those now swarming in the Pacific. In one bed of this kind, in the island of San Lorenzo, near Lima, Mr. Darwin found, at the altitude of 85 feet above the sea, pieces of cotton-thread, plaited rush, and the head of a stalk of Indian corn, the whole of which had evidently been imbedded with the shells. At the same height on the neighboring mainland, he found other signs cor- roborating the opinion that the ancient bed of the sea had there also been uplifted 85 feet, since the region was first peopled by the Peruvian race.* But similar shelly masses are also met with at much higher elevations, at innumerable points between the Chilian and Peruvian Andes and the sea-coast, in which no human remains were ever, or in all probability ever will Bes discovered. In the West Indies, also, in the island of Guadaloupe, a solid lime- stone occurs, at the level of the sea-beach, enveloping human skeletons. The stone is extremely hard, and chiefly composed of comminuted shell and coral, with here and there some entire corals and shells, of species now living in the adjacent ocean. ‘With them are included arrow-heads, fragments of pottery, and other articles of human workmanship. A limestone with similar contents has been formed, and is still forming, in St. Domingo. But there are also more ancient rocks in the West Indian Archipelago, as in Cuba, near the Havana, and in other islands, in which at; shells identical with those now living in corresponding lati- tudes ; some well-preserved, others in the state os casts, all referable to the post-pliocene period. I have already described in the seventh chapter, p. 84, what would be the effects of oscillations and changes of level in any region drained by a great river and its tributaries, supposing the area to be first depressed several hundred feet, and then re-elevated. I believe that such changes in the relative level of land and sea have actually occurred in the post- pliocene era in the hydrographical basin of the Mississippi and in that of the Rhine. The accumulation of fluviatile matter in a delta during a slow subsidence may raise the newly gained land superficially at the * Journal, p. 451. Cu. X.] PLAIN OF THE MISSISSIPPI. 121 same rate at which its foundations sink, so that these may go down hun- dreds or thousands of feet perpendicularly, and yet the sea bordering the delta may always be excluded, the whole deposit continuing to be terres- trial or freshwater in character. This appears to have happened in the deltas both of the Po and Ganges, for recent artesian borings, penetrating to the depth of 400 feet, have there shown that fluviatile strata, with shells of recent species, together with ancient surfaces of land supporting turf and forests, are depressed hundreds of feet below the sea level.* Should these countries be once more slowly upraised, the rivers would carve out valleys through the horizontal and unconsolidated strata as they rose, sweeping away the greater portion of them, and leaving mere frag- ments in the shape of terraces skirting newly-formed alluvial plains, as monuments of the former levels at which the rivers ran. Of this nature are “the bluffs,” or river cliffs, now bounding the valley of the Mississippi throughout a large portion of its “course.” The upper portions of these bluffs which at Natchez and elsewhere often rise to the height of 200 feet above the alluvial plain, consist of loam containing land and freshwater shells of the genera Helix, Pupa, Succinea, and Lymnea, of the same species as those now inhabiting the neighboring forests and swamps. In the same loam also are found the bones of the Mastodon, Elephant, Mega- lonyx, and other extinct quadrupeds.t I have endeavored to show that the deposits forming the delta and alluvial plain of the Mississippi consist of sedimentary matter, extend- ing over an area of 30,000 square miles, and known in some parts to be several hundred feet deep. Although we cannot estimate correctly how many years it may have required for the river to bring down from the upper country so large a quantity of earthy matter—the data for such a computation being as yet incomplete—we may still approximate to a minimum of the time which such an operation must have taken, by as- certaining experimentally the annual discharge of water by the Mississippi, and the mean annual amount of solid matter contained in its waters. The lowest estimate of the time required would lead us to assign a high an- tiquity, amounting to many tens of thousands of years to the existing delta, the origin of which is nevertheless an event of yesterday when con- trasted with the terraces formed of the loam above mentioned. The ma- terials of the bluffs were produced during the first part of a great oscilla- tion of level which depressed to a depth of 200 feet a larger area than the modern delta and plain of the Mississippi, and then restored the whole region to its former position.{ Loess of the Valley of the Rhine——A similar succession of geograph- ical changes attended by the production of a fluviatile formation, singu- larly resembling that which bounds the great plain of the Mississippi, seems to have occurred in the hydrographical basin of the Rhine, since * See Principles, 8th ed. pp. 260-268, 9th ed. 257-280. + See Principles of Geol. 9th ed., and Lyell’s Second Visit to the United States, vol. ii. p. 257. ¢ Lyell’s Second Visit to the United States, vol. ii. chap. 34. ‘ 122 LOESS OF THE VALLEY OF THE RHINE. [Gn ee the time when that basin had already acquired its present outline of hill and valley. I allude to the deposit provincially termed Joess in part of Germany, or /ehm in Alsace, filled with land and freshwater shells of existing species. It is a finely comminuted sand or pulverulent loam of a yellowish gray color, consisting chiefly of argillaceous matter combined with a sixth part of carbonate of lime, and a sixth of quartzose and micaceous sand. It often contains calcareous sandy concretions or nod- ules, rarely exceeding the size of a man’s head. Its entire thickness amounts, in some places, to between 200 and 300 feet; yet there are often no signs of stratification in the mass, except here and there at the bottom, where there is occasionally a sight intermixture of drifted ma- terials derived from subjacent rocks. Unsolidified as it is, and of so perishable a nature, that every streamlet flowing over it cuts out for. itself a deep gully, it usually terminates im a vertical cliff, from the sur- face of which land-shells are seen here and there to project in relief. In ~ all these features it presents a precise counterpart to the loess of the Mississippi. It is so homogeneous as generally to exhibit no signs of stratification, owing, probably, to its materials having been derived from a common source, and*having been accumulated by a uniform action. Yet it displays in some few places decided marks of successive deposi- tion, where coarser and finer materials alternate, especially near the bot- tom. Calcareous concretions, also inclosing land-shells, are sometimes arranged in horizontal layers. It is a remarkable deposit, from its posi- tion, wide extent, and thickness, its homogeneous mineral composition, and freshwater origin. Its distribution clearly shows that after the great valley of the Rhine, from Schaffhausen to Bonn, had acquired its present form, having its bottom strewed over with coarse gravel, a period arrived when it became filled up from side to side with fine mud, probably de- posited during river inundations ; and it is also clear that similar mud and silt were thrown down contemporaneously in the valleys of the prin- cipal tributaries of the Rhine. Thus, for example, it may be traced far into Wiirtemberg, up the val- ley of the Neckar, and from Frankfort, up the valley of the Main, to above Dettelbach. I have also seen it spreading over the country of Mayence, Eppelsheim, and Worms, on the left bank of the Rhine, and on the opposite side on the table-land above the Bergstrasse, between Wiesloch and Bruchsal, where it attains a thickness of 200 feet. Near Strasburg, large masses of it appear at the foot of the Vosges on the left bank, and at the base of the mountains of the Black Forest on the right bank. The Kaiserstuhl, a voleanic mountain which stands in the middle of the plane of the Rhine near Freiburg, has been covered almost every- where with this loam, as have the extinct volcanoes between Coblentz and Bonn. Near Andernach, in the Kirchweg, the loess containing the usual shells alternates with volcanic matter ; and over the whole are . strewed layers of pumice, lapilli, and voleanic sand, from 10 to 15 feet thick, very much resembling the ejections under which Pompeii lies buried. There is no passage at this upper junction from the loess into Cu. X.] LOESS OF THE RHINE. 123 the pumiceous superstratum ; and this last follows the slope of the hill, just as it would have done had it fallen in showers from the air on a declivity partly formed of loess. But, in general, the loess overlies all the volcanic products, even those between Neuwied and Bonn, which have the most modern aspect; and it has filled up in part the crater of the Roderberg, an extinct volcano near Bonn. In 1833 a well was sunk at the bottom of this crater, through 70 feet of loess, in part of which were the usual calcareous con- cretions. The interstratification above alluded to, of loess with layers of pumice and voleanic ashes, has led to the opinion that both during and since its deposition some of the last voleanic eruptions of the Lower Eifel have taken place. Should such a conclusion be adopted, we should be called upon to assign a very modern date to these eruptions. This curious _ point, therefore, deserves to be reconsidered ; since it may possibly have happened that the waters of the Rhine, swollen by the melting of snow ~ and ice, and flowing at a great height through a valley choked up with loess, may have swept away the loose superficial scori# and pumice of the Eifel volcanoes, and spread them out occasionally over the yellow loam. Sometimes, also, the melting of snow on the slope of small vol- canic cones may have given rise to local floods, capable of sweeping down light pumice into the adjacent low grounds. The first idea which has occurred to most geologists, after examining the loess between Mayence and Basle, is to imagine that a great lake once extended throughout the valley of the Rhine between those two places. Such a lake may have sent off large branches up the course of the Main, Neckar, and other tributary valleys, in all of which large patches of loess are now seen. The barrier of the lake might be placed somewhere in the narrow and picturesque gorge of the Rhine between Bingen and Bonn. But this theory fails altogether to explain the phe- nomena; when we discover that that gorge itself has once been filled with loess, which must have been tranquilly deposited in it, as also m the lateral valley of the Lahn, communicating with the gorge. The loess has also overspread the high adjoining platform near the village of Plaidt above Andernach. Nay, on proceeding farther down to the north, we discover that the hills which skirt the great valley between Bonn and Cologne have loess on their flanks, which also covers here and there the gravel of the plain as far as Cologne, and the nearest rising grounds. Besides these objections to the lake theory, the loess is met with near Basle, capping hills more than 1200 feet above the sea; so that a barrier of land capable of separating the supposed lake from the ocean would re- quire to be, at least, as high as the mountains called the Siebengebirge, near Bonn, the loftiest summit of which, the Oehlberg, is 1209 feet above the Rhine, and 1369 above the sea. It would be necessary, moreover, to place this lofty barrier somewhere below Cologne, or precisely where the level of the land is now lowest. Instead, therefore, of supposing one continuous lake of sufficient extent 124 LOESS OF THE RHINE [Ca X. and depth to allow of the simultaneous accumulation of the loess, at various heights, throughout the whole area where it now occurs, I formerly suggest- ed that, subsequently to the period when the countries now drained by the Rhine and its tributaries had nearly acquired their actual form and geo- graphical features, they were again depressed gradually by a movement like that now in progress on the west coast of Greenland.* In propor- tion as the whole district was lowered, the general fall of the waters between the Alps and the ocean was lessened; and both the main and lateral valleys, becoming more subject to river inundations, were partially filled up with fluviatile silt, containing land and freshwater shells. When a thickness of many hundred feet of loess had been thrown down slowly by this operation, the whole region was once more upheaved gradually. During this upward movement most of the fine loam would be carried off by the denuding power of rains and rivers; and thus the original valleys might have been re-excavated, and the country almost restored to its pristine state, with the exception of some masses and patches of loess such as still remain, and which, by their frequency smd remarkable ho- mogeneousness of composition and fossils, attest the ancient continuity and common origin of the whole. By imagining these oscillations of level, we dispense with the necessity of erecting and afterwards removing a mountain barrier sufficiently high to exclude the ocean from the valley of the Rhine during the period of the accumulation of the loess. The proportion of land shells of the genera Helix, Pupa, and Buli- mus, is very large in the loess; but in many places aquatic species of the genera Lymnea, Paludina, and Planorbis are also found. These; may have been carried away during floods from shallow pools and marshes bordering the river; and the great extent of marshy ground caused by the wide overflowings of rivers above supposed would favor the multiplication of amphibious mollusks, such as the Suceinea (fig. 106), which is almost everywhere characteristic of this formation, and is sometimes accompanied, as near Bonn, by another species, S. amphibia (fig. 34, p. 29). Among other abundant fossils are Helix plebeia and Pupa mscorum. (See Figures.) Both the terrestrial and aquatic shells preserved in the loess are of most fragile and delicate structure, and yet, Fig. 106. Fig. 107. Succinea elongata. Pupa muscorum Helix plebeia, they are almost invariably perfect and uninjured. They must have been broken to pieces had they been swept along by a violent inundation. Even the color of some of the land-shells, as that of Helix nemoralis, is occasionally preserved. * Princ. of Geol. 3d edition, 1834, vol. iii. p. 414. Cx. X.] AND ITS FOSSILS. 125 Bones of vertebrated animals are rare in the loess, but those of the mammoth, horse, and some other quadrupeds have been met with. At the village of Binningen, and the hills’ called Bruder Holz, near Basle, I found the vertebrz of fish, together with the usual shells. These ver- tebrze, according to M. Agassiz, belong decidedly to the Shark family, perhaps to the genus Zamna. In explanation of their occurrence among land and freshwater shells, it may be stated that certain fish of this fam- ily ascend the Senegal, Amazon, and other great rivers, to the distance of several hundred miles from the ocean.* - At Cannstadt, near Stuttgardt, in a valley also belonging to the hydro- graphical basin of the Rhine, I have seen the loess pass downwards into beds of calcareous tuff and travertin. Several valleys in northern Ger- many, as that of the Im at Weimar, and that of the Tonna, north of Gotha, exhibit similar masses of modern limestone filled with recent shells of the genera Planorbis, Lymnea, Paludina, &c., from 50 to 80 feet thick, with a bed of loess much resembling that of the Rhine, occa- sionally incumbent on them. In these modern limestones used for build- ing, the bones of Hlephas primigenius, Rhinoceros tichorinus, Ursus, speleus, Hyena spelea, with the horse, ox, deer, and other quadrupeds, occur; and in 1850 Mr. H. Credner and I obtained in a quarry at Ton- na, at the depth of 15 feet, inclosed in the calcareous rock and surrounded with dicotyledonous leaves and petrified leaves, four eggs of a snake of the size of the largest European Coluber, which, with three others, were lying im a series, or string. They are, I believe, the first reptilian remains which have been met with in strata of this age. The agreement of the shells in these cases with recent European species enables us to refer to a very modern period the filling up and re-excava- tion of the valleys; an operation which doubtless consumed a long period of time, since which the mammiferous fauna has undergone a considerable change. * Proceedings of Geol. Soc, No. 43, p. 222, 126 BOULDER FORMATION. [Ca. XL CHAPTER XI. NEWER PLIOCENE PERIOD—-BOULDER FORMATION. Drift of Scandinavia, northern Germany, and Russia—Its northern origin—Not all of the same age—Fundamental rocks polished, grooved, and scratched— Action of glaciers and icebergs—Fossil shells of glacial period—Drift of eastern Norfolk—Associated freshwater deposit—Bent and folded strata lying on un- disturbed beds—Shells on Moel Tryfane—Ancient glaciers of North Wales— Trish drift. Amonce the different kinds of alluvium described in the seventh chapter, mention was made of the boulder formation in the north of Europe, the peculiar characters of which may now be considered, as it belongs in part to the post-pliocene, and partly to the newer pliocene, period. I shall first allude briefly to that portion of it which extends from Finland and the Scandinavian mountains to the north of Russia, and the low countries bordering the Baltic, and which has been traced southwards as far as the eastern coast of England. This formation consists of mud, sand, and clay, sometimes stratified, but often wholly devoid of stratifica- tion, for a depth of more than a hundred feet. To this unstratified form of the deposit, the name of t2// has been applied in Scotland. It gen- erally contains numerous fragments of rocks, some angular and others rounded, which have been derived from formations of all ages, both fos- siliferous, volcanic, and hypogene, and which have often been brought from great distances. Some of the travelled blocks are of enormous size, several feet or yards in diameter; their average dimensions increas- ing as we advance northwards. The till is almost everywhere devoid of organic remains, unless where these have been washed into it from older formations; so that it is chiefly from relative position that we must hope to derive a knowledge of its age. Although a large proportion of the boulder deposit, or “ northern drift,” as it has sometimes been called, is made up of fragments brought from a distance, and which have sometimes travelled many hundred miles, the bulk of the mass in each locality consists of the ruins of subjacent or neighboring rocks ; so that it is red in a region of red sandstone, white in a chalk country, and gray or black in a district of coal and coal-shale. The fundamental rock on which the boulder formation reposes, if it consists of granite, gneiss, marble, or other hard stone capable of perma- nently retaining any superficial markings which may have been imprinted upon it, is usually smoothed or polished, and exhibits parallel striz and furrows having a determinate direction. This direction, both in Europe and North America, is evidently connected with the course taken by the erratic blocks in the same district being from north to south, or if it be 20 or 30 degrees to the east or west of north, always corresponding to the direction in which the large angular and rounded stones have travelled. Cu. XI] ROCKS DRIFTED BY ICE. 127 These stones themselves also are often furrowed and scratched on more than one side. In explanation of such phenomena I may refer the student to what was said of the action of glaciers and icebergs in the Principles of Geology (ch. xv.). It is ascertained that hard stones, frozen into a moving mass of ice, and pushed along under the pressure of that mass, scoop out long rectilinear furrows or grooves parallel to each other on the subjacent solid rock. (See fig. 109.) Smaller scratches and strie are made on Fig. 109. 4 Limestone polished, furrowed, and scratched by the glacier of Rosenlaui, in Switzerland. (Agassiz) a a, White streaks or scratches, caused by small grains of flint frozen into the ice. 6 6. Furrows. the polished surface by crystals or projecting edges of the hardest min- erals, just as a diamond cuts glass. The recent polishing and striation of limestone by coast-ice carrying boulders even as far south as the coast o1 Denmark, has been observed by Dr. Forchhammer, and helps us to conceive how large icebergs, running aground on the bed of the sea, may produce similar furrows on a grander scale. An account was given so long ago as the year 1822, by Scoresby, of icebergs seen by him drifting along in latitudes 69° and 70° N., which rose above the surface from 100 to 200 feet, and measured from a few yards to a mile in circumfer- ence. Many of them were loaded with beds of earth and rock, of such thickness that the weight was conjectured to be from 50,000 to 100,000 tons.* A similar transportation of rocks is known to be in progress in the southern hemisphere, where boulders included in ice are far more frequent than in the north. One of these icebergs was encountered in 1839, in mid-ocean, in the antarctic regions, many hundred miles from any known land, sailing northwards, with a large erratic block firmly * Voyages in 1822, p. 283. 128 - _ ORIGIN OF TILL. [Ca. XI. frozen into it. In order to understand in what manner long and straight grooves may be cut by such agency, we must remember that these float- ing islands of ice have a singular steadiness of motion, in consequence of the larger portion of their bulk being sunk deep under water, so that they are not perceptibly moved by the winds and waves even in the strongest gales. Many had supposed that the magnitude commonly attributed to icebergs by unscientific navigators was exaggerated, but now it appears that the popular estimate of tlreir dimensions has rather fallen within than beyond the truth. Many of them, carefully measured by the officers of the French exploring expedition of the Astrolabe, were between 100 and 225 feet high above water, and from 2 to 5 miles in length. Captain d’Urville ascertained one of them which he saw float- ing in the Southern Ocean to be 13 miles long and 100 feet high, with walls perfectly vertical. The submerged portions of such islands must, according to the weight of ice relatively to sea-water, be from six to eight times more considerable than the part which is visible, so that the mechan- ical power they might exert when fairly set in motion must be prodigious.* A large proportion of these floating masses of ice is supposed not to be de- rived from terrestrial glaciers,t but to be formed at the foot of cliffs by the drifting of snow from the land over the frozen surface of the sea. We know that in Switzerland, when glaciers laden with mud and stones melt away at their lower extremity before reaching the sea, they leave wherever they terminate a confused heap of unstratified rubbish, called “a moraine,” composed of mud, sand, and pieces of all the rocks with which they were loaded. We may expect, therefore, to find a formation of the same kind, resulting from the liquefaction of icebergs, in tranquil water. But, should the action of a current intervene at certain points or at certain seasons, then the materials will be sorted as they fall, and ar- ranged in layers according to their relative weight and size. Hence there will be passages from Z/, as it is called in Scotland, to stratified clay, gravel, and sand, and intercalations of one in the other. I have yet to mention another appearance connected with the boulder formation, which has justly attracted much attention in Norway and other parts of Europe. Abrupt pinnacles and outstanding ridges of rock are often observed to be polished and furrowed on the north side, or on the side facing the region from which the erratics have come; while, on the other, which is usually steeper and often perpendicular, called the “ lee- side,” such superficial markings are wanting. There is usually a collec- tion on this lee-side of boulders and gravel, or of large angular fragments. In explanation we may suppose that the north side was exposed, when still submerged, to the action of icebergs, and afterwards, when the land was upheaved, of coast-ice which ran aground upon shoals, or was packed on the beach; so that there would be great wear and tear on the sea- ward slope, while, on the other, gravel and boulders might be heaped up in a sheltered position. Northern origin of erratics—That the erratics of northern Europe * T. L. Hayes, Boston Journ. Nat. Hist. 1844. ¢ Principles, ch. xv. Cu. XL] STRATA CONTAINING RECENT SHELLS. 129 have been carried southward cannot be doubted; those of granite, for example, scattered over large districts of Russia and Poland, agree pre- cisely in character with rocks of the mountains of Lapland and Finland; while the masses of gneiss, syenite, porphyry, and trap, strewed over the low sandy countries of Pomerania, Holstein, and Denmark are identical in mineral characters with the mountains of Norway and Sweden. It is found to be a general rule in Russia, that the smaller blocks are carried to greater distances from their point of departure than the larger; the distance being sometimes 800 and even 1000 miles from the nearest rocks from which they were broken off; the direction having been from N. W. to S. E.,, or from the Scandinavian mountains over the seas and low lands to the southeast. That its accumulation throughout this area took place in part during the post-pliocene period is proved by its super- position at several points to strata containing recent shells. Thus, for example, in European Russia, MM. Murchison and De Verneuil found in 1840, that the flat country between St. Petersburg and Archangel, for a distance of 600 miles, consisted of horizontal strata, full of shells similar to those now ielabiting the arctic sea, on which nee the boulder forma- tion, ‘containing large erratics. In Sweden, in the immediate neighborhood of Upsala, I had observed, in 1834, a ridge of stratified sand and gravel, in the midst of which occurs a layer ee marl, evidently formed originally at the bottom of the Baltic, by the slow growth of the mussel, cockle, and other marine shells of living spe- cies, intermixed with some proper to freshwater. The marine shells are all of dwarfish size, like those now inhabiting the brackish waters of the Baltic; and the marl, in which myriads of them are imbedded, is now raised more than 100 fegt above the level of the Gulf of Bothnia. Upon the top of this ridge repose several huge erratics, consisting of gneiss for the most part unrounded, from 9 to 16 feet in diameter, and which must haye been brought into their present position since the time when the neighboring gulf was already characterized by its peculiar fauna.* Here, therefore, we have proof that the transport of erratics continued to take place, not merely when the sea was inhabited by the existing testacea, but when the north of Europe had already assumed that remarkable feature of its physical geography, which separates the Baltic from the North Sea, and causes the Gulf of Bothnia to have only one-fourth of the saltness belonging to the ocean. In Denmark, also, recent shells have been found in stratified beds, closely associated with the boulder clay. It was stated that in Russia the erratics diminished generally in size in proportion as they are traced farther from their source. The same observation holds true in regard to the average bulk of the Scandinavian boulders, when we pursue them southwards, from the south of Norway and Sweden through Denmark and Westphalia. This phenomenon is in perfect harmony with the theory of ice-islands floating in a sea of * See paper by the author, Phil. Trans. 1835. p. 15. 9 130 FOSSILS OF ARCTIC SPECIES. [Ca. XL variable depth; for the heavier erratics require icebergs of a larger size to buoy them up; and even when there are no stones frozen in, more than seven-eighths, and often nine-tenths, of a mass of drift-ice is under water. The greater, therefore, the volume of the iceberg, the sooner would it impinge on some shallower part of the sea; while the smaller and lighter floes, laden with finer mud and gravel, may pass freely over the same banks, and be carried to much greater distances. In those places, also, where in the course of centuries blocks have been carried southwards by coast-ice, having been often stranded and again set afloat in the direction of a prevailing current, the blocks will diminish im size the farther they travel from their point of departure for two reasons: first, because they will be repeatedly exposed to wear and tear by the action of the waves; secondly, because the largest blocks are seldom without di- visional planes or “joints,” which cause them to split when weathered. Hence as often as they start on a fresh yoyage, becoming buoyant by coast-ice which has frozen on to them, one portion of the mass is detached from the rest. A recent examination (in 1852) of several trains of huge erratics in lat, 42° 50’ N. in the United States, in Berkshire, on the west- ern confines of Massachusetts, has convinced me that this cause has been very influential both in reducing the size of erratics, and in restoring an- gularity to blocks which would otherwise be rounded in proportion to their distance from their original starting point. The “northern drift” of the most southern latitudes is usually of the highest antiquity. In Scotland it rests immediately on the older rocks, and is covered by stratified sand and clay, usually devoid of ‘fossils, but in which, at certain points near the east and west coast, as, for example, in the estuaries of the Tay and Clyde, marine shells haye been discovered. The same shells have also been met with in the north, at Wick in Caith- ness, and on the shores of the Moray Frith. The principal deposit on the Clyde occurs at the height of about 70 feet, but a few shells have Fig, 110, Fig. 111. Astarte borealis, Leda oblonga. Fig. 112. Fig. 113. Fig. 114. Fig. 115. Sawicava rugosa. Pecten islandicus. Natica clausa. Trophon clathratum, Northern shells common in the drift of the Clyde, in Scotland. ‘been traced in it as high as 554 feet above the sea. Although a propor ‘tion of between 85 or 90 in 100 of the imbedded shells are of recent ‘species, the remainder are unknown; and even many which are recent Cz. XI] NORFOLK DRIFT, ETC. 131 now inhabit more northern seas, where we may, perhaps, hereafter find living representatives of some of the unknown fossils. The distance to which erratie. blocks have been carried southwards in. Scotland, and the course they have taken, which is often wholly independent of the present position of hill and valley, favors the idea that ice-rafts rather than gla- ciers were in general the transporting agents. The Grampians in For- farshire and in Perthshire are from 3000 to 4000 feet high. To the southward lies the broad and deep valley of Strathmore, and to the south of this again rise the Sidlaw Hills* to the height of 1500 feet and upwards. On the highest summits of this chain, formed of sandstone and shale, and at various elevations, are found huge angular fragments of mica-schist, some 3 and others 15 feet in diameter, which have been conveyed for a distance of at least 15 miles from the nearest Grampian rocks from which they could have been detached. Others have been left strewed over the bottom of the large intervening vale of Strath- more. Still farther south on the Pentland Hills, at the height of 1100 feet above the sea, Mr. Maclaren has observed a fragment of mica-schist weighing from 8 to 10 tons, the nearest mountain composed of this for- mation being 50 miles distant.t The testaceous fauna of the boulder period, in Scotland, England, and Ireland, has been shown by Prof. E. Forbes to contain a much smaller number of species than that now belonging to the British seas, and to have been also much less rich in species than the Older Pliocene fauna of the crag which preceded it. Yet the species are nearly all of them now living either in the British or more northern seas, the shells of more aretic latitudes being the most abundant and the most wide spread throughout the entire area of the drift from north to south. This extensive range of the fossils can by no means be explained by imagining the mollusca of the drift to have been inhabitants of a deep sea, where a more uniform temperature prevailed. On the contrary, many species were littoral, and others belonged to a shallow sea, not above 100 feet deep, and very few of them lived, according to Prof. E. Forbes, at greater depths than 300 feet. From what was before stated it will appear that the boulder formation displays almost everywhere, in its mineral ingredients, a strange hetero- geneous mixture of the ruins of adjacent lands, with stones both angular and rounded, which have come from points often very remote. Thus we find it in our eastern counties, as in Norfolk, Suffolk, Cambridge, Hunt- ingdon, Bedford, Hertford, Essex, and Middlesex, containing stones from the Silurian and Carboniferous strata, and from the lias, oolite, and chalk, all with their peculiar fossils, together with trap, syenite, mica-schist, granite, and other crystalline rocks. A fine example of this singular - mixture extends to the very suburbs of London, being seen on the summit of Muswell Hill, Highgate. But south of London the northern * See above, section, p. 48. + Geol. of Fife, &e. p. 220. 132 NORFOLK DRIFT AND (Cx. Xa. drift is wanting, as, for example, in the Wealds of Surrey, Kent, and Sussex. Norfolk drift—The drift can nowhere be studied more advantageous- ly in England than in the cliffs of the Norfolk coast between Happisburgh and Cromer. Vertical sections, having an ordinary height of from 50 to 70 feet, are there exposed to view for a distance of about 20 miles. The name of diluvium was formerly given to it by those who supposed it to have been produced by the violent action of a sudden and transient deluge, but the term drift has been substituted by those who reject this hypothesis. Here, as elsewhere, it consists for the most part of clay, loam, and sand, in part stratified, in part devoid of stratification. Peb- bles, together with some large boulders of granite, porphyry, green- stone, lias, chalk, and other transported rocks, are interspersed, especially through the till. That some of the granitic and other fragments came from Scandinavia I have no doubt, after having myself traced the course of the continuous stream of blocks from Norway and Sweden to Den- mark, and across the Elbe, through Westphalia, to the borders of Hol- land. We need not be surprised to find them reappear on our eastern coast, between the Tweed and the Thames, regions not half so remote from parts of Norway as are many Russian erratics from the sources whence they came. White chalk rubble, unmixed with foreign matter, and even huge fragments of solid chalk, also occur in many localities in these Norfolk cliffs. No fossils have been detected in this drift, which can positively be referred to the era of its accumulation ; but at some points it overlies a freshwater formation containing recent shells, and at others it is blended with the same in such a manner as to force us to conclude that both were contemporaneously deposited. Fig. 116. Grayel Sand Till The shaded portion consists of Freshwater beds. Intercalation of freshwater beds and of boulder clay and sand at Mundesley. This interstratification is expressed in the annexed figure, the dark mass indicating the position of the freshwater beds, which contain much vege- Fig. 117. Paludina marginata, Michaud. (P. minuta, Strickland.) The middle figure is of the natural size. Ca. XT] ASSOCIATED FRESHWATER STRATA. 133. table matter, and are divided into thin layers. The imbedded shells be- long to the genera Planorbis, Lymnea, Paludina, Unio, Cyclas, and others, all of British species, except a minute Paludina, now inhabiting France. (See fig. 117.) The Cyclas (fig. 118) is merely a remarkable variety of the common English species. The scales and teeth of fish of the genera Pike, Perch, Fig. 118. Cyclas (Pisidiwm) amnica, var.? The two middle figures are of the natural size. Roach, and others, accompany these shells ; but the species are not con- sidered by M. Agassiz to be identical with known British or European kinds. The series of formations in the cliffs of eastern Norfolk, now under consideration, beginning with the lowest, is as follows :—First, chalk ; secondly, patches of a marine tertiary formation, called the Norwich Crag, hereafter to be described; thirdly, the freshwater beds already mentioned ; and lastly, the drift. Immediately above the chalk, or crag, when that is present, is found here and there a buried forest, or a stra- tum in which the stools and roots of trees stand in their natural position, the trunks having been broken short off and imbedded with their branches and leaves. It is very remarkable that the strata of the over- lying boulder formation have often undergone great derangement at points where the subjacent forest-bed and chalk remain undisturbed. There are also cases where the upper portion of the boulder deposit has been greatly deranged, while the lower beds of the same have continued horizontal. Thus the annexed section (fig. 119) represents a cliff about Fig. 119. Cliff 50 feet high between Bacton Gap and Mundesley. 50 feet high, at the bottom of which is é/, or unstratified clay, contain- ing boulders having an even horizontal surface, on which repose con- formably beds of laminated clay and sand about 5 feet thick, which, in their turn, are succeeded by vertical, bent, and contorted layers of sand and loam 20 feet thick, the whole being covered by flint gravel. Now the curves of the variously colored beds of loose sand, loam, and pebbles 134 MASSES OF CHALK IN DRIFT. (Cu. XL are so complicated that not only may we sometimes find portions of them which maintain their verticality to a height of 10 or 15 feet, but they have also been folded upon themselves in such a manner that con- tinuous layers might be thrice pierced in one perpendicular boring. At some points there is an apparent’ folding of the beds round a cen- tral nucleus, as at a, fig 120, where the strata seem bent round a small . Fig. 121 | << wW sh Fig. 120. Folding of the strata between East Section of concentric beds west of Cromer. and West Runton. 1. Blue clay. 3. Yellow Sand. 2. White sand. 4, Striped loam and clay. 5. Laminated blue clay. mass of chalk; or, as in fig. 121, where the blue clay, No. 1, is in the centre; and where the other strata, 2, 3, 4, 5, are coiled round it; the entire mass being 20 feet in perpendicular height. This appearance of concentric arrangement around a nucleus is, nevertheless, delusive, being produced by the intersection of beds bent into a convex shape; and that which seems the nucleus being, in fact, the innermost bed of the series, which has become partially visible by the removal of the protuberant portions of the outer layers. To the north of Cromer are other fine illustrations of contorted drift reposing on a floor of chalk horizontally stratified and having a level sur- face. These phenomena, in themselves sufficiently difficult of explanation, are rendered still more anomalous by the occasional inclosure in the drift of huge fragments of chalk many yards in diameter. One striking in- stance occurs west of Sherringham, where an enormous pinnacle of chalk, between 70 and 80 feet in height, is flanked on both sides by vertical layers of loam, clay, and gravel. (Fig. 122.) This chalky fragment is only one of many detached masses which have been included in the drift, and forced along with it into their present position. The level surface of the chalk in situ (d) may be traced for miles along the coast, where it has escaped the violent movements to which the incumbent drift has been exposed.* We are called upon, then, to explain how any force can have been exerted against the upper masses, so as to produce movements in which the subjacent strata have not participated. It may be answered that, if * For a full account of the drift of East Norfolk, see a paper by the author Phil. Mag. No. 104, May, 1840. Cx. XI] MASSES OF CHALK IN DRIFT. 135 Fig. 122. Included pinnacle of chalk at Old Hythe point, west of Sherringham. d. Chalk with regular layers of chalk flints. ce. Layer called * the pan,” of loose chalk, flints, and marine shells of recent species, cemented by oxide of iron. we conceive the é// and its boulders to have been drifted to their present place by ice, the lateral pressure may have been supplied by the strand- ing of ice-islands. We learn from the observations of Messrs. Dease and Simpson in the polar regions, that such islands, when they run aground, push before them large mounds of shingle and sand. It is therefore probable that they often cause great alterations in the arrangement of pliant and incoherent strata forming the upper part of shoals or sub- merged banks, the inferior portions of the same remaining unmoved. Or many of the complicated curvatures of these layers of loose sand and grayel may have been due to another cause, the melting on the spot of icebergs and coast-ice in which successive deposits of pebbles, sand, ice, snow, and mud, together with huge masses of rock fallen from cliffs, may have become interstratified. Ice-islands so constituted often capsize when afloat, and gravel once horizontal may have assumed, before the associa- ted ice was melted, an inclined or vertical position, The packing of ice forced up on a coast may lead to similar derangement in a frozen con- glomerate of sand or shingle, and, as Mr. Trimmer has suggested,* alter- nate layers of earthy matter may have sunk down slowly during the lique- faction of the intercalated ice, so as to assume the most fantastic and anomalous positions, while the strata below, and those afterwards thrown down above, may be perfectly horizontal. There is, however, still another mode in which some of these bendings may have been produced. When a railway embankment is thrown across a marsh or across the bed of a drained lake, we frequently find that the foundation, consisting of peat and shell-marl, or of quicksand and mud, gives way, and sinks as fast as the embankment is raised at the top. At the same time, there is often seen at the distance of many yards, in some neighboring part of the morass, a squeezing up of pliant strata, the amount of upheaval depending on the volume and weight of mate- * Quart. Journ. Geol. Soc. vol. vii. p. 22. 136 BURIED FOREST IN NORFOLK. [Ca XL rials heaped upon the embankment. In 1852 I saw a remarkable in- stance of such a downward and lateral pressure, in the suburbs of Boston (U.§.), near the South Cove. With a view of converting part of an es- tuary overflowed at high tide into dry land, they had thrown into it a vast load of stones and sand, upwards of 900,000 cubic yards in volume. Under this weight the mud had sunk down many yards vertically. Mean- while the adjoining bottom of the estuary, supporting a dense growth of salt-water plants, only visible at low tide, had been pushed gradually up- ward, in the course of many months, so as to project five or six feet above high-water mark. The upraised mass was bent into five or six anticlinal folds, and below the upper layer of turf, consisting of salt-marsh plants, mud was seen above the level of high tide, full of sea shells, such as Mya arenaria, Modiola plicatula, Sanguinolaria fusca, Nassa obsoleta, Natica triseriata, and others. In some of these curved beds the layers of shells were quite vertical. The upraised area was 75 feet wide, and several hun- dred yards long. Were an equal load, melted out of icebergs or coast-ice ° thrown down on the floor of a sea, consisting of soft mud and sand, similar disturbances and contortions might result in some adjacent pliant strata, yet the underlying more solid rocks might remain undisturbed, and newer formations, perfectly horizontal, might be afterwards superimposed. - A buried forest has been adverted to as underlying the drift on the coast of Norfolk. At the time when the trees grew, there must have been dry land over a large area, which was afterwards submerged, so as to allow a mass of stratified and unstratified drift, 200 feet and more in thickness, to be superimposed. The undermining of the cliffs by the sea in modern times has enabled us to demonstrate, beyond all doubt, the fact of this superposition, and that the forest was not formed along the present coast-line. Its situation implies a subsidence of several hundred feet since the commencement of the drift period, after which there must have been an upheaval of the same ground; for the forest bed of Nor- folk is now again so high as to be exposed to view at many points at low water; and this same upward movement may explain why the wd, which is conceived to have been of submarine origin, is now met with far inland, and on the summit of hills. The boulder formation of the west of England, observed in Lanca- shire, Cheshire, Shropshire, Staffordshire, and Worcestershire, contains in some places marine shells of recent species, rising to various heights, from 100 to 350 feet above the sea. The erratics have come partly from the mountains of Cumberland, and partly from those of Scotland. But it is on the mountains of North Wales that the “ Northern drift,” with its characteristic marine fossils, reaches its greatest altitude. On Moel Tryfane, near the Menai Straits, Mr. Trimmer met with shells of the species commonly found in the drift at the height of 1392 feet above the level of the sea. It is remarkable that in the same neighborhood where there is evi- dence of so great a submergence of the land during part of the glacial period, we have also the most decisive proofs yet discovered in the British Ca, XID] FOSSIL REMAINS IN DRIFT. 137 Isles of sub-aerial glaciers. Dr. Buckland published in 1842 his reasons for believing that the Snowdonian mountains in Caernarvonshire were former- ly covered with glaciers, which radiated from the central heights through the seven principal valleys of that chain, where strize and flutings are seen on the polished rocks directed towards as many different points of the compass. He also described the “moraines” of the ancient glaciers, and the rounded “ bosses” or small flattened domes of polished rock, such as the action of moving glaciers is known to produce in Switzerland, when gravel, sand, and boulders, underlying the ice, are forced along over a foundation of hard stone. Mr. Darwin, and subsequently Prof. Ramsay, ‘have confirmed Dr. Buckland’s views in regard to these Welsh glaciers. Nor indeed was it to be expected that geologists should discover proofs of icebergs having abounded in the area now occupied by the British Isles in the Pleistocene period without sometimes meeting with the signs of contemporaneous glaciers which covered hills even of moderate elevation _ between the 50th and 60th degrees of latitude. In Ireland the “ drift” exhibits the same general characters and fossil re- mains as in Scotland and England ; but in the southern part of that island, Prof. E. Forbes and Capt. James found in it some shells which show that the glacial sea communicated with one inhabited by a more southern fauna. Among other species in the south, they mention at Wexford and elsewhere the occurrence of Nucula Cobboldic (see fig. 125, p. 155) and Turritella incrassata (a crag fossil); also a southern form of Musus, and a Mitra allied to a Spanish’ species.* CHAPTER XII. Difficulty of interpreting the phenomena of drift before the glacial hypothesis was adopted—Effects of intense cold in augmenting the quantity of alluyium—- Analogy of erratics and scored rocks in North America and Europe—Bayfield on shellsin drift of Canada—Great subsidence and re-elevation of land from the sea, required to account for glacial appearances—-Why organic remains so rare in northern drift—Mastodon giganteus in United States—Many shells and some quadrupeds survived the glacial cold—Alps an independent centre of dispersion of erraties—Alpine blocks on the Jura—Whether transported by glaciers or floating ice—Recent transportation of erratics from the Andes to Chiloe—Me- teorite in Asiatic drift. Iv will appear from what was said in the last chapter of the marine shells characterizing the boulder formation, that nine-tenths or more of them belong to species still living. The superficial position of “the drift” is in perfect accordance with its imbedded organic remains, leading us to refer its origin to a modern period. If, then, we encounter so much dif- ficulty in the interpretation of monuments relating to times so near our own—if in spite of their recent date they are involved in so much ob- scurity—the student may ask, not without reasonable alarm, how we can hope to decipher the records of remoter ages. * Forbes, Memoirs of Geol. Survey of Great Britain, vol. i. p. 877. 188 - GLACIAL PHENOMENA — [Cu. XIL To remove from the mind as far as possible this natural feeling of discouragement, I shall endeavor in this chapter to prove that what seems most strikingly anomalous, in the “erratic formation,” as some call it, is really the result of that glacial action which has already been alluded to. If so, it was to be expected that so long as the true origin of so singular a deposit remained undiscovered, erroneous theories and terms would be invented in the effort to solve the problem. These inventions would inevitably retard the reception of more correct views which a wider field of observation might afterwards suggest. The term “diluvium” was. for a time the popular name of the boul- der formation, because it was referred by some to the deluge, while others retained the name as expressive of their opinion that a series of diluvial waves raised by hurricanes and storms, or by earthquakes, or by the sudden upheaval of land from the bed of the sea, had swept over the continents, carrying with them vast masses of mud and heavy stones, and forcing these stones over rocky surfaces so as to polish and imprint upon them long furrows and striz. But no explanation was offered why such agency should have been developed more energetically in modern times than at former periods of the earth’s history, or why it should be displayed in its fullest intensity in northern latitudes; for it is important to insist on the fact, that the boulder formation is a northern phenomenon. Even the southern ex- tension of the drift, or the large erratics found in the Alps and the surrounding lands, especially their occurrence round the highest parts of the chain, offers such an exception to the general rule as confirms the glacial hypothesis; for it shows that the transportation of stony frag- ments to great distances, and the striation, polishing, and grooving of solid floors of rock, are here again intimately connected with accumula- tions of perennial snow and ice. That there is some intimate connection between a cold or northern climate and the various geological appearances now commonly called glacial, cannot be doubted by any one who has compared the countries bordering the Baltic with those surrounding the Mediterranean. The smoothing and striation of rocks and erratics are traced from the sea- shore to the height of 3000 feet above the level of the Baltic, whereas such phenomena are wholly wanting in countries bordering the Mediter- ranean; and their absence is still more marked in the equatorial parts of Asia, Africa, and America; but when we cross the southern tropic, and reach Chili and Patagonia, we again encounter the boulder formation, between the latitude 41° S. and Cape Horn, with precisely the same characters which it assumes in Europe. The evidence as to climate derived from the organic remains of the drift is, as we have seen, in perfect harmony with the conclusions above alluded to, the former habits of the species of mollusca being accurately ascertainable, inasmuch as they belong to species still living, and known to have at present a wide range in northern seas. But if we are correct in assuming that the northern hemisphere was Cu. XIL] OF NORTHERN ORIGIN. 189 considerably colder than now during the period under consideration, owing probably to the greater area and height of arctic lands, and to the quantity of icebergs which such a geographical state of things would generate, it may be well to reflect before we proceed farther on the en- tire modification-which extreme cold would produce in the operation of those causes spoken of in the sixth chapter as most active in the forma- tion of alluvium. A large part of the materials derived from the detritus of rocks, which in warm climates would go to form deltas, or would be regularly stratified by marine currents, would, under arctic influences, assume a superficial and alluvial character. Instead of mud being carried farther from a coast than sand, and sand farther out than pebbles,—instead of dense stratified masses being heaped up in limited areas, along the borders of continents,—nearly the whole materials, whether coarse or fine, would be conveyed by ice to equal distances, and huge fragments, which water alone could never move, would be borne for hundreds of miles without having their edges worn or fractured; and the earthy and stony masses, when melted out of the frozen rafts, would be scattered at random over the sub- marine bottom, whether on mountain tops or in low plains, with scarcely any relation to the inequalities of the ground, settling on the crests or ridges of hills in tranquil water as readily as in valleys and ravines. Occasionally, in those deep and uninhabited parts of the ocean, never reached by any but the finest sediment in a normal state of things, the bottom would become densely overspread by gravel, mud, and boulders. In the Western Hemisphere, both in Canada and as far south as the 40th and even 38th parallel of latitude in the United States, we meet with a repetition of all the peculiarities which distinguish the European boulder formation. Fragments of rock have travelled for great distances from north to south; the surface of the subjacent rock is smoothed, striated, and fluted; unstratified mud or t/2 containing boulders is asso- ciated with strata of loam, sand, and clay, usually devoid of fossils. Where shells are present, they are of species still living in northern seas, and half of them identical with those already enumerated as belonging to European drift 10 degrees of latitude farther north. The fauna also of the glacial epoch in North America is less rich in species than that now inhabiting the adjacent sea, whether in the Gulf of St. Lawrence, or off the shores of Maine, or in the Bay of Massachusetts. At the southern extremity of its course, moreover, it presents an analogy with the drift of the south of Ireland, by blending with a more southern fauna, as for example at Brooklyn near New York, in lat. 419° N., where, according to MM. Redfield and Desor, Venus mercenaria and other southern species of Shells begin to occur as fossils in the drift. The extension on the American continent of the range of erratics during the Pleistocene period to lower latitudes than they reached in Europe, agrees well with the present southward deflection of the isother- mal lines, or rather the lines of equal winter temperature. It seems that formerly, as now, a more extreme climate and a more abundant supply of floating ice prevailed on the western side of the Atlantic. 140 DRIFT SHELLS IN CANADA. [Ox XI. Another resemblance between the distribution of the drift fossils in Europe and North America has yet to be pointed out. In Norway, Sweden, and Scotland, as in Canada and the United States, the marine shells are confined to very moderate elevations above the sea (between 100 and 700 feet), while the erratic blocks and the grooved and pol- ished surfaces of rock extend to elevations of several thousand feet. I described in 1839 the fossil shells collected by Captain Bayfield from strata of drift at Beauport, near Quebec, in lat. 47°, and drew from them the inference that they indicated a more northern climate, the shells agreeing in great part with those of Uddevalla in Sweden.* The shelly beds attain at Beauport and the neighborhood a height of 200, 300, and sometimes 400 feet above the sea, and dispersed through some of them are large boulders of granite, which could not have been propelled by a violent current, because tne accompanying fragile shells are almost all entire. They seem, therefore, said Captain Bayfield, writing in 1838, to have been dropped down from melting ice, like similar stones which are now annually deposited in the St. Lawrence. I visited this locality in 1842, and made the annexed section, fig. 123, Fig. 123. K. Mr. Ryland’s house. d. Drift, with boulders of syenite, &c, kh, Clay and sand of higher grounds, with ¢. Yellow sand. Saxicawva, &e. b. Laminated clay, 25 feet thick. g. Gravel with boulders. A. Horizontal lower Silurian strata, J Mass of Saxicawa rugosa, 12 feet thick. B. Valley re-excavated. ce. Sand and loam with Mya truncata, Scalaria Graentandica, &e. which will give an idea of the general position of the drift in Canada and the United States. I imagine that the whole of the valley B was once filled up with the beds 8, ¢, d, e, f, which were deposited during a period of subsidence, and that subsequently the higher country (2) was submerged and overspread with drift. The partial re-excavation of B took place when this region was again uplifted above the sea to its present height. Among the twenty-three species of fossil shells collected by me from these beds at Beauport, all were of recent northern species, except one, which is unknown as living, and may be extinct (see fig. 124). I also examined the same formation farther up the valley of the St. Lawrence, in the suburbs of Montreal, where some of the beds of loam are filled with great numbers of the Mytilus edulis, or our common European mussel, retaining both its valves and purple color. This shelly deposit, containing Sazicava rugosa and other characteristic marine shells, _* Geol. Trans. 2d series, vol. vi. p.135. Mr. Smith of Jordanhill had arrived at similar conclusions as to climate from the shells of the Scotch Pleistocene deposits, + Proceedings of Geol. Soc. No. 63, p. 119. Cz. XIL] SUBSIDENCE IN DRIFT PERIOD. 141 Fig. 124. Astarte Laurentiana. a, Outside. 6. Inside of right valve. ec. Left valve. % also occurs at an elevated point on the mountain of Montreal, 450 feet above the level of the sea.* Tn my account of Canada and the United States, published in 1845, I announced the conclusion to which I had then arrived, that to explain the position of the erratics and the polished surfaces of rocks, and their strie and flutings, we must assume first a gradual submergence of the land in North America, after it had acquired its present outline of hill and valley, cliff and ravine, and then its re-emergence from the ocean. When the land was slowly sinking, the sea which bordered it was covered with islands of floating ice coming from the north, which, as they grounded on the coast and on shoals, pushed along such loose materials of sand and pebbles as lay strewed over the bottom. By this force all angular and projecting points were broken off, and fragments of hard stone, frozen into the lower surface of the ice, had power to scoop out grooves in the subjacent solid rock. The sloping beach, as well as the floor of the ocean, might be polished and scored by this machinery; but no flood of water, however violent, or however great the quantity of de- tritus or size of the rocky fragments swept along by it, could produce such long, perfectly straight and parallel furrows, as are everywhere visi- ble in the Niagara district, and generally in the region north of the 40th parallel of latitude.t By the hypothesis of such a slow and gradual subsidence of the land we may account for the fact that almost everywhere in N. America and Northern Europe the boulder formation rests on a polished and furrowed surface of rock,—a fact by no means obliging us to imagine, as some think, that the polishing and grooving action was, as a whole, anterior in date to the transportation of the erratics. During the successive depres- sion of high land, varying originally in height from 1000 to 3000 feet above the sea-level, every portion of the surface would be brought down by turns to the level of the ocean, so as to be converted first into a coast- line, and then into a shoal; and at length, after being well scored by the stranding upon it, year after year, of large masses of coast-ice, and occa- sional icebergs, might be sunk to a depth of several hundred fathoms. By the constant depression of land, the coast would recede farther and farther from the successively formed zones of polished and striated rock, each outer zone becoming in its turn so deep under water as to be no longer grated upon by the heaviest icebergs. Such sunken areas would then simply serve as receptacles of mud, sand, and boulders dropped from melting ice, perhaps * Travels in N. America, vol. ii. p, 141. + Ibid. p. 99, chap. xix. 142 STRIATED PEBBLES AND BOULDERS. [Cu. XIL to a depth scarcely, if at all inhabited by testacea and zoophytes. Mean- while, during the formation of the unstratified and unfossiliferous mass in deeper water, the smoothing and furrowing of shoals and beaches would still go on elsewhere upon and near the coast in full activity. If at length the subsidence should cease, and the direction of the movement of the earth’s crust be reversed, the sunken area covered with drift would be slowly re- converted into land. The boulder deposit, before emerging, would then for a time be brought within the action of the waves, tides, and currents, so that its upper portion, being partially disturbed, oul fe its oven als re- arranged and stratified. Streams also flowin from the land would in some places throw down layers of sediment upon the #//. In that case, the order of superposition will be, first and uppermost, sand, loam, and gravel occasionally fossiliferous; secondly, an unstratified and unfossilifer- ous mass, called idl, for the most part of much older date than the pre- ceding, with angular erratics, or with boulders interspersed; and, thirdly, beneath the whole, a surface of polished and furrowed rock. Such a succession of events seems to have prevailed very widely on both sides of the Atlantic, the travelled blocks having been carried in general from the North Pole southwards, but mountain chains having in some cases served as independent centres of dispersion, of which the Alps present the most conspicuous example. It is by no means rare to meet with boulders imbedded in drift which are worn flat on one or more of their sides, the surface being at the same time polished, furrowed, and striated. They may have been so shaped in a glacier before they reached the sea, or when they were fixed in the bottom of an iceberg as it ran aground. We learn from Mr. Charles Martins that the glaciers of Spitzbergen project from the coast tnto a sea between 100 and 400 feet deep; and that numbers of striated pebbles or blocks are there seen to disengage themselves from the overhanging masses of ice as they melt, so as to fall at once into deep water.* That they should retain such markings when again upraised above the sea ought not to surprise us, when we remember that rippled sands, and the eracks in clay dried between high and low water, and the foot-tracks of animals and rain-drops impressed on mud, and other superficial markings, are all found fossil in rocks of various ages. On the other hand, it is not difficult to account for the absence in many districts of striated and scored pebbles and boulders in glacial deposits, for they may have been exposed to the action of the waves on a coast while it was sinking beneath or rising above the sea. Noshingle on an ordinary sea-beach exhibits such striz, and at avery short distance from the termination of a glacier every stone in the bed of the torrent which gushes out from the melting ice is found to have lost its glacial markings by being rolled for a distance even of a few hundred yards. The usual dearth of fossil shells in glacial clays well fitted to preserve organic remains may, perhaps, be owing, as already hinted, to the * Bulletin Soc. Géol. de France, tom. iv, 2de sér. p. 1121. Cx. XID] MASTODON GIGANTEUS. 148 absence of testacea in the deep sea, where the undisturbed accumulation of boulders melted out of coast-ice and icebergs may take place. In the f®gean and other parts of the Mediterranean, the zero of animal life, according to Prof. E. Forbes, is approached at a depth of about 3800 fathoms. In tropical seas it would descend farther down, just as vegeta- tion ascends higher on the mountains of hot countries. Near the pole, on the other hand, the same zero would be reached much sooner both on the hills and in the sea. If the ocean was filled with floating bergs, and a low temperature prevailed in the northern hemisphere during the glacial period, even the shallow part of the sea might have been unin- habitable, or very thinly peopled with livmg beings. It may also be remarked that the melting of ice in some fiords in Norway freshens the water so as to destroy marine life, and famines have been caused in Ice- land by the stranding of icebergs drifted from the Greenland. coast, which have required several years to melt, and have not only injured. the hay harvest by cooling the atmosphere, but have driven away the fish from the shore by chilling and freshening the sea. If the cold of the glacial epoch came on slowly, if it was long before it reached its greatest intensity, and again if it abated gradually, we may expect to find the earliest and latest formed drift less barren of organic remains than that deposited during the coldest period. We may also expect that along the southern limits of the drift during the whole gla- cial epoch, there would be an intimate association of transported matter of northern origin with fossil-bearing sediment, whether marine or fresh- water, belonging to more southern seas, rivers, and continents. That in the United States, the Mastodon giganteus was very abundant after the drift period is evident from the fact that entire skeletons of this animai are met with in bogs and lacustrine deposits occupying hollows in the drift. They sometimes occur in the bottom even of small ponds recently drained by the agriculturist for the sake of the shell marl. I ex- amined one of these spots at Geneseo in the state of New York, from which the bones, skull, and tusk of a Mastodon had been procured in the marl below a layer of black peaty earth, and ascertained that all the associated freshwater and land shells were of a species now common in the same district. They consisted of several species of Lymnea, of Pla- norbis bicarinatus, Physa heterostropha, &e. Tn 1845 no less than six skeletons of the same species of Mastodon were found in Warren county, New Jersey, 6 feet below the surface, by a farmer who was digging out the rich mud from a small pond which he had drained. Five of these skeletons were lying together, and a large part of the bones crumbled to pieces as soon as they were exposed to the air. But nearly the whole of the other skeleton, which lay about 10 feet apart from the rest, was preserved entire, and proved the correctness of Cuvier’s conjecture respecting this extinct animal, namely, that it had twenty ribs like the living elephant. From the clay in the interior within the ribs, just where the contents of the stomach might naturally have been looked for, seven bushels of vegetable matter were extracted. 144 EXTINCT MAMMALIA ABOVE DRIFT. [Cu. XIL I submitted some of this matter to Mr. A. Henfrey, of London, for microscopic examination, and he informs me that it consists of pieces of small twigs of a coniferous tree of the Cypress family, probably the young shoots of the white cedar, Thuja occidentalis, still a native of North America, on which therefore we may conclude that this extinct Mastodon once fed. Another specimen of the same quadruped, the most complete and probably the largest ever found, was exhumed in 1845 in the town of Newburg, New York, the length of the skeleton being 25 feet, and its height 12 feet. The anchylosing of the last two ribs on the right side afforded Dr. John C. Warren a true gauge for the space occupied by the intervertebrate substance, so as to enable him to form a correct estimate of the entire length. The tusks when discovered were 10 feet long, but a part only could be preserved. The large proportion of animal matter in the tusk, teeth, and bones of some of these fossil mammalia is truly astonishing. It amounts in some cases, as Dr. C. T. Jackson has ascer- tained by analysis, to 27 per cent., so that when all the earthy ingre- dients are removed by acids, the form of the bone remains as perfect, and the mass of animal matter is almost as firm, as in a recent bone subjected to similar treatment. It would be rash, However to infer from such data that these quadru- peds were mired in modern times, unless we use that term strictly in a geological sense. I have shown that there is a fluviatile deposit in the valley of the Niagara, containing shells of the genera Melania, Lymnea, Planorbis, Valvata, Cyclas, Unio, Helix, &c., all of recent species, from which the bones of the great Mastodon have been taken in a very perfect state. Yet the whole excavation of the ravine, for many miles below the Falls, has been slowly effected since that fluviatile deposit was thrown down. Whether or not, in assigning a period of more than 30,000 years for the recession of the Falls from Queenstown to their present site, I have over or under estimated the time required for that operation, no one can doubt that a vast number of centuries must have elapsed before so great a series of geographical changes were brought about as have occurred since the entombment of this elephantine quadruped. ‘The freshwater gravel which incloses it is decidedly of much more modern origin than the drift or boulder clay of the same region.* Other extinct animals accompany the Mastodon giganteus in the post- glacial deposits of the United States, among which the Castorozdes ohi- oensis, Foster and Wyman, a huge rodent allied to the beaver, and the Capybara may be mentioned. But whether the “loess,” and other freshwater and marine strata of the Southern States, in which skeletons of the same Mastodon are mingled with the bones of the Megatherium, Mylodon, and Megalonyx, were contemporaneous with the drift, or were of subsequent date, is a chronological question still open to discussion. * See Travels in N. America, vol. i. chap. ii, and Principles of Geol. chap xiv. Cx. XII] CLIMATE OF DRIFT PERIOD. 145 It appears clear, however, from what we know of the tertiary fossils of Europe—and I believe the same will hold true in North America—that many species of testacea and some mammalia, which existed prior to the glacial epoch, survived that era. As European examples among the warm- blooded quadrupeds, the Hlephas primigenius and Rhinoceros tichorinus may be mentioned. As to the shells, whether freshwater, terrestrial, or marine, they need not be enumerated here, as allusion will be made to them in the sequel, when the pliocene tertiary fossils of Suffolk are described. The fact is important, as refuting the hypothesis that the cold of the glacial period was so intense and universal as to annihilate all living creatures throughout the globe. That the cold was greater for a time than it is now in certain parts of Siberia, Europe, and North America, will not be disputed; but, before we can infer the universality of a colder climate, we must ascertain what was the condition of other parts of the northern, and of the whole south- ern, hemisphere at the time when the Scandinavian, British, and Alpine erratics were transported into their present position. It must not be for- gotten that a great deposit of drift and erratic blocks is now in full pro- gress of formation in the southern hemisphere, in a zone corresponding in latitude to the Baltic, and to Northern Italy, Switzerland, France, and England. Should the uneven bed of the southern ocean be hereafter converted by upheaval into land, the hills and valleys will be strewed over with transported fragments, some derived from the antarctic conti- nent, others from islands covered with glaciers, like South Georgia, which must now be centres of the dispersion of drift, although situated in a latitude, agreeing with that of the Cumberland mountains in Eng- land. Not only are these operations going on between the 45th and 60th parallels of latitude south of the line, while the corresponding zone of Europe is free from ice; but, what is still more worthy of remark, we find in the southern hemisphere itself, only 900 miles distant from South Georgia, where the perpetual snow reaches to the sea-beach, lands covered with forests, as in Terra del Fuego, There is here no difference of lati- tude to account for the luxuriance of vegetation in one spot, and the absolute want of it in the other; but among other refrigerating causes in South Georgia may be enumerated the countless icebergs which float from the antarctic zone, and which chill, as they melt, the waters of the ocean, and the surrounding air, which they fill with dense fogs. I have endeayored in the “ Principles of Geology,” chapters 7 and 8, to point out the intimate connection of climate and the physical geogra- phy of the globe, and the dependence of the mean annual temperature, not only on the height of the dry land, but on its distribution in high or low latitudes at particular epochs. If, for example, at certain periods of the past, the antarctic land was less elevated and less extensive than now, while that at the north pole was higher and more continuous, the conditions of the northern and southern hemispheres might have been the reverse of what we now witness in regard to climate, although the i 10 146 ALPINE ERRATICS. [Cu. XIT mountains of Scandinavia, Scotland, and Switzerland, may have béen less elevated than at present. But if in both of the polar regions a considerable area of elevated dry land existed, such a concurrence of re- frigerating conditions in both hemispheres might have created for a time an intensity of cold never experienced since ; and such probably was the state of things during that period of submergence to which I have alluded in this chapter. ) Alpine erratics—Although the arctic regions constitute the great centre from which erratics have travelled southwards in all directions in Europe and North America, yet there are some mountains, as I have already stated, like those of North Wales and the Alps, which have served as separate and independent centres for the dispersion of blocks. In illustration of this fact, the Alps deserve particular attention, not only from their magnitude, but because they lie beyond the ordinary limits of the “northern drift” of Europe, being situated between the 44th and 47th degrees of north latitude. On the flanks of these mountains, and on the Subalpine ranges of hills or plains adjoining them, those appear- ances which have been so often alluded to, as distinguishing or accom- panying the drift, between the 50th and 70th parallels of north latitude, suddenly reappear, to assume in a more southern country their most exaggerated form. Where the Alps are highest, the largest erratic blocks have been sent forth, as, for example, from the regions of Mont Blane and Monte Rosa, into the adjoining parts of France, Switzerland, Austria, and Italy, while in districts where the great chain sinks in altitude, as in Carinthia, Carniola, and elsewhere, no such rocky fragments, or a few only, and of smaller bulk, have been detached and transported to a distance. In the year 1821, M. Venetz first announced his opinion that the Alpine glaciers must formerly have extended far beyond their present limits, and the proofs appealed to by him in confirmation of this doctrine were afterwards acknowledged by M. Charpentier, who strengthened them by new observations anil arguments, and declared, in 1836, his conyiction that the glaciers of the Alps must once have reached as far as the Jura, and have carried thither their moraines across the great valley of Switzerland. M. Agassiz, after several excursions in the Alps with M. Charpentier, and after devoting himself some years to the study of glaciers, published, in 1840, an admirable description of them, and of the marks which attest the former action of great masses of ice over the entire surface of the Alps and the surrounding country.* ‘He pointed out that the surface of every large glacier is strewed over with gravel and stones detached from the surrounding precipices by frost, rain, light- ning, or avalanches. And he described more carefully than preceding writers the long lines of these stones, which settle on the sides of the ‘glacier, and are called the lateral moraines; those found at the lower ‘end of the ice being called terminal moraines. Such heaps of earth and * Acassiz, Etudes sur les Glaciers, and Systéme Glaciere. Cu. XII] MORAINES OF GLACIERS. 147 boulders every glacier pushes before it when advancing, and leaves behind it when retreating. When the Alpine glacier reaches a lower and warmer situation, about 3000 or 4000 feet above the sea, it melts so rapidly that, in spite of the downward movement of the mass, it can advance no farther. Its precise limits are variable from year to year, and still more so from century to century; one example being on record of a recession of half a mile in a single year. We also learn from M. Venetz, that whereas, between the eleventh and fifteenth centuries, all the Alpine glaciers were less advanced than now, they began in the seventeenth and eighteenth centuries to push forward so as to cover roads formerly open, and to overwhelm forests of ancient growth. These oscillations enable the geologist to note the marks which a gla- cier leaves behind it as it retrogrades, and among these the most promi- nent, as before stated, are the terminal moraines, or mounds of unstrati- fied earth and stones, often divided by subsequent floods into hillocks, which cross the valley like ancient earth-works, or embankments made to dam up a river. Some of these transverse barriers were formerly pointed out by Saussure below the glacier of the Rhone, as proving how far it had once transgressed its present boundaries. On these moraines we see many large angular fragments, which, having been carried along on the surface of the ice, have not had their, edges worn off by friction ; but the greater number of the boulders, even those of large size, have been well rounded, not by the power of water, but by the mechanical force of the ice, which has pushed them against each other, or against the rocks flanking the valley. Others have fallen down the numerous fissures which intersect the glacier, where, being subject to the pressure of the whole mass of ice, they have been forced along, and either well rounded or ground down into sand, or even the finest mud, of which the moraine is largely constituted. As the terminal moraines are the most prominent of all the monu- ments left by a receding glacier, so are they the most liable to oblitera- tion ; for violent floods or debacles are often occasioned in the Alps by the sudden bursting of what are called glacier-lakes. These temporary sheets of water are caused by the damming up of a river by a glacier which has increased during a succession of cold seasons, and descending from a tributary into the main valley, has crossed it from side to side. On the failure of this icy barrier, the accumulated waters are let loose, which sweep away and level many a transverse mound of gravel and loose boulders below, and spread their materials in confused and irregular beds over the river-plain. Another mark of the former action of glaciers, in situations where they exist no longer, is the polished, striated, and grooved surfaces of rocks already alluded to. Stones which lie underneath the glacier and are pushed along by it, sometimes adhere to the ice, and as the mass glides slowly along at the rate of a few inches, or at the utmost, two or three feet, per day, abrade, groove, and polish the rock, and the larger blocks are reciprocally grooved and polished by the rock on their lower 148 ALPINE ERRATICS. (Ca. XIL sides. As the forces both of pressure and propulsion are enormous, the sand, acting like emery, polishes the surface; the pebbles, like coarse gravers, scratch and furrow it; and the large stones scoop out grooves in it. Another effect also of this action, not yet adverted to, is called “roches moutonnées.” Projecting eminences of rock are smoothed and worn into the shape of flattened domes, where the glaciers have passed over them. Although the surface of almost every kind of rock, when exposed in the open air, wastes away by decomposition, yet some retain for ages their polished and furrowed exterior; and, if they are well protected by a coy- ering of clay or turf, these marks of abrasion seem capable of enduring forever. They have been traced in the Alps to great heights above the present glaciers, and to great horizontal distances beyond them. There are also found, on the sides of the Swiss valleys, round and deep holes, with polished sides, such holes as waterfalls make in the solid rock, but in places remote from running waters, and where the form of the surface will not permit us to suppose that any cascade could ever have existed. Similar cavities are common in hard rocks, such as gneiss, in Sweden, where they are called giant caldrons, and are sometimes 10 feet and more in depth; but in the Alps and Jura they often pass into spoon-shaped excavations and prolonged gutters. We learn from M. Agassiz that hollows of this form are now cut out by streams of water, which, after flowing along the surface of a glacier, fall into open fissures in the ice and form a cascade. Here the falling water, causing the gravel and sand at the bottom to rotate, cuts out a round cavity in the rock. But as the glacier moves on, the cascade becomes locomotive, and what would otherwise have been a circular hole is prolonged into a deep groove. The form of the rocky bottom of the valley down which the glacier is moving causes the rents in the ice and these locomotive cascades to be formed again and again, year after year, in exactly the same spots. Another effect of a glacier is to lodge a ring of stones round the sum- mit of a conical peak which may happen to project through the ice. If the glacier is lowered greatly by melting, these circles of large angular fragments, which are called “perched blocks,” are left in a singular situa- tion near the top of a steep hill or pinnacle, the lower parts of which may be destitute of boulders. Alpine blocks on the Jura—Now some or all the marks above enu- merated,—the moraines, erratics, polished surfaces, domes, striz, cal- drons, and perched rocks, are observed in the Alps at great heights above the present glaciers, and far below their actual extremities; also in the great valley of Switzerland, 50 miles broad; and almost every- where on the Jura, a chain which lies to the north of this valley. The average height of the Jura is about one-third that of the Alps, and it is now entirely destitute of glaciers, yet it presents almost everywhere similar moraines, and the same polished and grooved surfaces, and water- worn cavities. The erratics, moreover, which cover it, present a phenom- enon which has astonished and perplexed the geologist for more than half a century. No conclusion can be more incontestable than that these Cu. XIL] ON THE JURA. 149 angular blocks of granite, gneiss, and other crystalline formations, came from the Alps, and that they have been brought for a distance of 50 miles and upwards across one of the widest and deepest valleys of the world, so that they are now lodged on the hills and valleys of a chain composed of limestone and other formations, altogether distinct from those of the Alps. Their great size and angularity, after a journey of so many leagues, has justly excited wonder; for hundreds of them are as large as cottages; and one in particular, celebrated under the name of Pierre A Bot, rests on the side of a hill about 900 feet above the lake of Neufchatel, and is no less than 40 feet in diameter. It will be remarked that these blocks on the Jura offer an exception to the rule before laid down, as applicable in general to erratics, since they have gone from south to north. Some of the largest masses of granite and gneiss have been found to contain 50,000 and 60,000 cubic feet of stone, and one limestone block at Devens, near Box, which has travelled 30 miles, contains 161,000 cubic feet, its angles being sharp and unworn.* Von Buch, Escher, and Studer have shown, from an examination of the mineral composition of the boulders, that those on the western Jura, near Neufchatel, have come from the region of Mont Blane and the Valais; those on the middle parts of the Jura from the Bernese Ober- Jand; and those on the eastern Jura from the Alps of the small cantons, Glaris, Schwytz, Uri, and Zug. The blocks, therefore, of these three great districts have been derived from parts of the Alps nearest to the localities in the Jura where we now find them, as if they had crossed the great valley in a direction at right angles to its length: the most western stream having followed the course of the Rhone; the central, that of the Aar; and the eastern, that of the two great rivers, Reuss and Limmat. The non-intermixture of these groups of travelled frag- ments, except near their confines, was always regarded as most enig- matical by those who adopted the opinion of Saussure, that they were all whirled along by a rapid current of muddy water rushing from the Alps. M. Charpentier first suggested, as before mentioned, that the Swiss glaciers once reached continuously to the Jura, and conveyed to them these erratics; but at the same time he conceived that the Alps were formerly higher than now. M. Agassiz, on the other hand, instead of introducing distinct and separate glaciers, suggested that the whole valley of Switzerland might have been filled with ice, and that one great sheet of it extended from the Alps to the Jura, when the two chains were of the same height as now relatively to each other. Such an hypothesis labors under this difficulty, that the difference of altitude, when distributed over a space of 50 miles, gives an inclination of no more than two de- grees, or far less than that of any known glaciers. It has, however, since received the able support of Professor James Forbes, in his excellent work on the Alps, published in 1843. * Archiac, Hist. des Progrés, &e. vol. ii. p. 249. 150 . ERRATICS OF THE JURA. [Cx In the theory which I formerly advanced, jointly with Mr. Darwin,* it was suggested that the erratics may have been transferred by floating ice to the Jura, at the time when the greater part of that chain, and the whole of the Swiss valley to the south, was under the sea. At that period the Alps may have attained only half their present altitude, and may yet have constituted a chain as lofty as the Chilian Andes, which, in a latitude corresponding to Switzerland, now send down glaciers to the head of every sound, from which icebergs, covered with blocks of granite, are floated seaward.t Opposite that part of Chili where the glaciers abound is situated the island of Chiloe, 100 miles in length, with a breadth of 30 miles, running parallel to the continent. The channel which separates it from the main land is of considerable depth, and 25 miles broad. Parts of its surface, like the adjacent coast of Chili, are overspread with recent marine shells, showing an upheaval of the land during a very modern period; and beneath these shells is a boulder deposit, in which Mr. Darwin found large travelled blocks. One grcup of fragments were of granite, which had evidently come from the Andes, while in another place angular blocks of syenite were met with. Their arrangement may have been due to successive crops of icebergs issuing from different sounds, to the heads of which glaciers descend from the Andes. These icebergs, taking their departure year after year from distinct points, may have been stranded repeatedly, in equally distinct groups, in bays or creeks of Chiloe, and on islets off the coast, so that the stones trans- ported by them might hereafter appear, some on hills and others in valleys, should that country and the bed of the adjacent sea be ever upheaved. A continuance in future of the elevatory movement, in the region of the Andes and of Chiloe, might cause the former chain to rival the Alps in altitude, and give to Chiloe a height equal to that of the Jura. The same rise might dry up the channel between Chiloe and the main land, so that it would then represent the great valley of Switzerland. In the course of these changes, all parts of Chiloe and the intervening strait, haying in their turn been a sea-shore, may have been polished and scratched by eoast-ice, and by innumerable icebergs running aground and grating on the bottom. If we apply this hypothesis to Switzerland and the Jura, we are by no means precluded from the supposition that, in proportion as the land acquired additional height, and the bed of the sea emerged, the Jura itself may have had its glaciers; and those existing in the Alps, which had at first extended to the sea, may, during some part of the period of upheaval, have been prolonged much farther into the valleys than now. At a later period, when the climate grew milder, these glaciers may have entirely disappeared from the Jura, and may have receded in the Alps to their present limits, leaving behind them in both districts those moraines which now attest the greater extension of the ice in former times.f * See Elements of Geology, 2d ed. 1841. + Darwin’s Journal, p. 283. + More recently Sir R. Murchison, having revisited the Alps, has declared his Us. XII] METEORITES IN DRIFT. it Meteorites in drift—Before concluding my remarks on the northern drift of the Old World, I shall refer to a fact recently announced, the discovery of a meteoric stone at a great depth in the alluvium of North- ern Asia. ~ Erman, in his Archives of Russia for 1841 (p. 314), cites a very cir- cumstantial account drawn up by a Russian miner of the finding of a mass of meteoric iron in the auriferous alluvium of the Altai. Some sinall fragments of native iron were first met with in the gold-washings of Petropawlowsker in the Mrassker Circle; but though they attracted attention, 1t was supposed that they must have been broken off from the tools of the workmen. At length, at the depth of 31 feet 5 inches from the surface, they dug out a piece of iron we'ghing 174 pounds, of a steel-gray color, somewhat harder than ordinary iron, and, on analyzing it, found it to consist of native iron, with a small proportion of nickel, as usual in meteorie stones. It was buried in the bottom of the deposit where the gravel rested on a flaggy limestone. Much brown iron ore, as well as gold, occurs in the same gravel, which appears to be part of that extensive auriferous formation in which the bones of the mammoth, the Rhinoceros tichorhinus, and other extinct quadrupeds abound. No sufficient data are supplied to enable us to determine whether it be of Post-Pliocene or Newer Pliocene date. We ought not, I think, to feel surprise that we have not hitherto succeeded in detecting the signs of such aérolites in older rocks, for, besides their rarity in our own days, those which fell into the sea (and it is with marine strata that geologists have usually to deal), being chiefly composed of native iron, would rapidly enter into new chemical combi- nations, the water and mud being charged with chloride of sodium and other salts. We find that anchors, cannon, and other cast-iron imple- ments which have been buried for a few hundred years off our English coast have decomposed in part or entirely, turning the sand and gravel which inclosed them into a conglomerate, cemented together by oxide of iron. In like manner meteoric iron, although its rusting would .be some- what checked by the alloy of nickel, could scarcely ever fail to decompose in the course of thousands of years, becoming oxide, sulphuret, or car- bonate of iron, and its origin being then no longer distinguishable. The greater the antiquity of rocks,—the oftener they have been heated and cooled, permeated by gases or by the waters of the sea, the atmosphere or mineral springs,—the smaller must be the chance of meeting with a mass of native iron unaltered; but the preservation of the ancient meteorite of the Altai, and the presence of nickel in these curious bodies, renders the recognition of them in deposits of remote periods less hope- less than we might have anticipated. opinion that “the great granitic blocks of Mont Blanc were translated to the Jura when the intermediate country was under Waters Paper read to Geol. Soc. London, May 30, 1849. 152 NEWER PLIOCENE STRATA. [Cz. XIIL- CHAPTER XII NEWER PLIOCENE STRATA AND CAVERN DEPOSITS. Chronological classification of Pleistocene formations, why difficult—Freshwater deposits in valley of Thames—In Norfolk cliffs—In Patagonia—Comparative longevity of species in the mammalia and testacea—Fluvio-marine crag of Norwich—Newer Pliocene strata of Sicily—Limestone of great thickness and elevation—Alternation of marine and volcanic formations—Proofs of slow accu- mulation—Great geographical changes in Sicily since the living fauna and flora began to exist—Osseous breccias and cavern deposits—Sicily—Kirkdale— Origin of stalactite—Australian cave-breccias—Geographical relationship of the provinces of living vertebrata and those of the fossil species of the Pliocene periods—Extinct struthious birds of New Zealand—Teeth of fossil quadrupeds. Havine in the last chapter treated of the boulder formation and its: associated freshwater and marine strata as belonging chiefly to the close of the Newer Pliocene period, we may now proceed to other deposits of the same or nearly the same age. It should, however, be stated that it is difficult to draw the line of separation between these modern forma- tions, especially when we are called upon to compare deposits of marine and freshwater origin, or these again with the ossiferous contents of caverns. If as often as the carcasses of quadrupeds were buried in alluvium during floods, or mired in swamps, or imbedded in lacustrine strata, a stream of lava had descended and preserved the alluvial or freshwater deposits, as frequently happened in Auvergne (see above, p. 80), keeping them free from intermixture with strata subsequently formed, then indeed the task of arranging chronologically the whole series of mammaliferous formations might have been easy, even though many species were common to several successive groups. But when there have been oscillations in the lévels of the land, accompanied by the widening and’ deepening of valleys at more than one period,—when the same surface has sometimes been submerged beneath the sea, after supporting forests and land quadrupeds, and then raised again, and subject during each change of level to sedimentary deposition and partial denudation,—and when the drifting of ice by marine currents or by rivers, during an epoch of intense cold, has for a season interfered with the ordinary mode of transport, or with the geographical range of species, we cannot hope speedily to extricate ourselves from the confusion in which the classifica- tion of these Pleistocene formations is involved. At several points in the valley of the Thames, remnants of ancient fluviatile deposits occur, which may differ considerably in age, although the imbedded land and freshwater shells in each are of recent species. At Brentford, for example, the bones of the Siberian Mammoth, or Cu. XIIL] DEPOSITS IN VALLEY OF THAMES. 153 Elephas primigenius, and the Rhinoceros tichorhinus, both of them quad- rupeds of which the flesh and hair have been found preserved in the frozen soil of Siberia, occur abundantly, with the bones of an hippopot- amus, aurochs, short-horned ox, red deer, reindeer, and great cave-tiger or lion.* A similar group has been found fossil at Maidstone, in Kent, and other places, agreeing in general specifically with the fossil bones detected in the caverns of England. When we see the existing reindeer and an extinct hippopotamus in the same fluviatile loam, we are tempted to indulge our imaginations in speculating on the climatal conditions which could haye enabled these genera to coexist in the same region. Wherever there is a continuity of land from polar to temperate and equa- torial regions, there will always be points where the southern limit of an arctic species meets the northern range of a southern species; and if one or both have migratory habits, like the Bengal tiger, the American bison, the musk ox, and others, they may each penetrate mutually far into the respective provinces of the other. There may also have been several oscillations of temperature during the periods which immediately pre- ceded and followed the more intense cold of the glacial epoch. The strata bordering the left bank of the Thames at Grays Thurrock, in Essex, are probably of older date than those of Brentford, although the associated land and freshwater shells are nearly all, if not all, identi- cal with species now living. Three of the shells, however, are no longer inhabitants of Great Britain; namely, Paludina marginata (fig. 117, p. 133), now living in France; Unio littoralis (fig. 29, p. 28), now inhab- iting the Loire; and Cyrena consobrina (fig. 26, p. 28). The last- mentioned fossil (a recent Egyptian shell of the Nile) is very abundant at Grays, and deserves notice, because the genus Cyrena is now no longer European. The rhinoceros occurring in the same beds (R. leptorhinus, see fig. 136, p. 167), is of a different species from that of Brentford above men- tioned, and the accompanying elephant belongs to the variety called Filephas meridionalis, which, according to MM. Owen and H. von Meyer, two high authorities, is the same species as the Siberian mammoth, although some naturalists regard it as distinct. With the above mam- malia is also found the Hippopotamus major, and what is most remark- able in so modern and northern a deposit, a monkey, called by Owen Macacus pliocenus. The submerged forest already alluded to (p. 137) as underlying the drift at the base of the cliffs of Norfolk is associated with a bed of lignite and loam, in which a great number of fossil bones occur, apparently of the same group as that of Grays, just mentioned. It has sometimes been called “the Elephant bed.” One portion of it, which stretches out under the sea at Happisburgh, was overgrown in 1820 by a bank of recent oysters, and there the fishermen dredged up, according to Wood- ward, in the course of thirteen years, together with the oysters, above * Morris, Geol. Soc. Proceed. 1849. 154 FLUVIO-MARINE NORWICH CRAG. [Ca. XMM. 2000 mammoths’ grinders.* Another portion of the same continucus stratum has yielded at Bacton, Cromer, and. other places on the coast, the bones of a gigantic beaver (Z’rogontherium Cuvieri, Fischer), as well as the ox, horse, and deer, and both species of rhinoceros, 2. tichorhinus and &. leptorhinus. In studying these and various other similar assemblages of fossils, we have a good exemplification of the more rapid rate at which the mam- miferous fauna, as compared to the testaceous, diverges from the recent type when traced backwards in time. I have before hinted, that the longevity of species in the class of warm-blooded quadrupeds is not so great as in that of the mollusea, the latter having probably more capacity for enduring those changes of climate and other external circumstances, and those revolutions in the organic world, which in the course of ages occur on the earth’s surface. This phenomenon is by no means confined to Europe, for Mr. Darwin found at Bahia Blanea, in South America, Jat. 39° S., near the northern confines of Patagonia, fossil remains of the extinct mammiferous genera Megatherium, Megalonyx, Toxodon, and others, associated with shells, almost all of species already ascertained to be still living in the contigu- ous sea ;+ the marine mollusca, as well as those of rivers, lakes, or the land, having died out more slowly than the terrestrial mammalia. I alluded before (p. 131) to certain marine strata overlying till near Glasgow, and at other points on the Clyde, in which the shells are for the most part British, with an intermixture of some arctic species; while others, about a tenth of the whole, are supposed to be extinet. This formation may also be called Newer Pliocene. Fluvio-marine crag of Norwich.—At several places within five miles of Norwich, on both banks of the Yare, beds of sand, loam, and gravel, provincially termed “crag,” but of a very different age from the Suffolk crag, occur, in which there is a mixture of marine, land, and freshwater shells, with ichthyolites and bones of mammalia. It is clear that these beds have been accumulated at the bottom of the sea near the mouth of a river. They form patches of variable thickness, resting on white chalk, and are covered by a dense mass of stratified flint gravel. The surface of the chalk is often perforated to the depth of several inches by the Pholas crispata, each fossil shell still remaining at the bottom of its cylindrical cavity, now filled up with loose sand which has fallen from the incumbent crag. > This species of Pholas still exists and drills the rocks between high and low water on the British coast. The most common shells of these strata, such as Fusus striatus, Turritella terebra, Cardium edule, and Cyprina islandica, are now abundant in the Bnitish seas; but with them are some extinct species, such as Wucula Cobboldie (fig. 125) and Tel- lina obligua (fig. 126). Natica helicoides (fig. 127) is an example of a species formerly known only as fossil, but which has now been found living in our seas. Among the accompanying bones of mammalia is the Jfastodon * Woodward’s Geology of Norfolk. + Zool. of Beagle, part 1, pp. 9, 111. Ux. XIIT] NORWICH CRAG—PLEISTOCENE. Fig. 125. Fig. 126. Natica helicoides, Nucula Cobboldia. Tellina obliqua. Johnston, arvernensis* (see fig. 135, p. 165), a portion of the upper jawbone with a tooth haying been found by Mr. Wigham at Postwick, near Norwich. As this species has also been found in the Red Crag, both at Sutton and at Felixstow, and had hitherto been regarded as characteristic of forma- tions older than the Pleistocene, it may possibly have been washed out of the Red into the Norwich Crag. . Among the bones, however, respecting the authenticity of which there seems no doubt, may be mentioned those of the elephant, horse, pig, deer, and the jaws and teeth of field mice (fig. 146, p. 167). I have seen the tusk of an elephant from Bramerton near Norwich, to which many serpulz were attached, showing that it had lain for some time at the bottom of the sea of the Norwich Crag. At Thorpe, near Aldborough, and at Southwold, in Suffolk, this fluvio- marine formation is well exposed in the sea-cliffs, consisting of sand, shingle, loam, and laminated clay. Some of the strata there bear the marks of tranquil deposition, and in one section a thickness of 40 feet is sometimes exposed to view. Some of the lamelli-branchiate shells have both valves united, although mixed with land and freshwater testacea, and with the bones and teeth of elephant, rhinoceros, horse, and deer. Captain Alexander, with whom I examined these strata in 1835, showed me a bed rich in marine shells, in which he had found a large specimen of the Fusus striatus, filled with sand, and in the interior of which was the tooth of a horse. Among the freshwater shells I obtained the Cyrena consobrina (fig. 26, p- 28), before mentioned, supposed to agree with a species now living in the Nile. I formerly classed the Norwich Crag as older Pliocene, conceiving that more than a third of the fossil testacea were extinct; but there now seems good reason for believing that several of the rarer shells obtained from these strata do not really belong to a contemporary fauna, but have been washed out of the older beds of the “Red Crag;” while other species, once supposed to have died out, have lately been met with living in the British seas. According to Mr. Searles Wood, the total number of marine species does not exceed seventy-six, of which one tenth only are extinct. Of the fourteen associated freshwater shells, all the species appear to be living. Strata containing the same shells as those near Norwich have been found by Mr. Bean, at Bridlington, in Yorkshire. * Owen, Brit. Foss. Mamm. 271. Jastodon longirostris, Kaup, see ibid. 156 NEWER PLIOCENE STRATA. [Cu. XIIL Newer Pliocene Strata of Sicily.—In no part of Europe are the Newer Pliocene formations seen to enter so largely into the structure of the earth’s crust, or to rise to such heights above the level of the sea, as in Sicily. They cover nearly half the island, and near its centre, at Cas- trogiovanni, they reach an elevation of 3000 feet. They consist princi- pally of two divisions, the upper calcareous, the lower argillaceous, both of which may be seen at Syracuse, Girgenti, and Castrogiovanni. According to Philippi, to whom we are indebted for the best account of the tertiary shells of this island, thirty-five species out of one hundred and twenty-four obtained from the beds in central Sicily are extinct. Of the remainder, which still live, five species are no longer inhabitants of the Mediterranean. When I visited Sicily in 1828 I estimated the pro- portion of living species as somewhat greater, partly because I con- founded with the tertiary formation of central Sicily the strata at the base of Etna, and some other localities, where the fossils are now proved to agree entirely with the present Mediterranean fauna. Philippi came to the conclusion, that in Sicily there is a gradual pas- sage from beds containing 70 per cent. of recent shells, to those in which the whole of the fossils are identical with recent species; but his tables appear scarcely to bear out so important a generalization, several of the places cited by him in confirmation having as yet furnished no more than twenty or thirty species of testacea. The Sicilian beds in question probably belong to about the same period as the Norwich Crag, although a geologist, accustomed to see nearly all the Pleistocene formations in the north of Europe occupying low grounds and very incoherent in tex- ture, is naturally surprised to behold formations of the same age so solid and stony, of such thickness, and attaining so great an elevation above the level of the sea. The upper or calcareous member of this group in Sicily consists in some places of a yellowish-white stone, like the caleaire grossier of Paris, in others, of a rock nearly as compact as marble. Its aggregate thick- ness amounts sometimes to 700 or 800 feet. It usually occurs in regular horizontal beds, and is occasionally intersected by deep valleys, such as those of Sortino and Pentalica, in which are numerous caverns. The fossils are in every stage of preservation, from shells retaining portions of their animal matter and color, to others which are mere casts. The limestone passes downwards into a sandstone and conglomerate, below which is clay and blue marl, like that of the Subappenine hills, from which perfect shells and corals may be disengaged. The clay sometimes alternates with yellow sand. South of the plain of Catania is a region in which the tertiary beds are intermixed with volcanic matter, which has been for the most part the product of submarine eruptions. It appears that, while the clay, sand, and yellow limestone before mentioned were in course of deposition at the bottom of the sea, voleanoes burst out beneath the waters, like that of Graham Island, in 1831, and these explosions recurred again and again at distant intervals of time. Volcanic ashes and sand were showered Cx. XIIL] OF SICILY. 157 down and spread by the waves and currents so as to form strata of tuff, which are found intercalated between beds of limestone and clay contain- ing marine shells, the thickness of the whole mass exceeding 2000 feet. The fissures through which the lava rose may be seen in many places forming what are called dikes. In part of the region above alluded to, as, for example, near Lentini, a conglomerate occurs in which I observed many pebbles ‘of volcanic rocks covered by full grown serpule. We may explain the origin of these by supposing that there were some small volcanic islands which may have been destroyed from time to time by the waves, as Graham Island has been swept away since 1831. The rounded blocks and pebbles of solid voleanic matter, after being rolled for a time on the beach of such temporary islands, were carried at length into some tran- quil part of the sea, where they lay for years, while the marine serpule adhered to them, their shells growing and covering their surface, as they are seen adhering to the shell figured in p. 22. Finally, the bed of peb- bles was itself covered with strata of shelly limestone. At Vizzini, a town not many miles distant to the 8. W., I remarked another striking proof of the gradual manner in which these modern rocks were formed, and the long intervals of time which elapsed between the pouring out of distinct sheets of lava. A bed of oysters no less than 20 feet in thick- | ness rests upon a current of basaltic lava. The oysters are perfectly iden- tifiable with our common eatable species. Upon the oyster bed, again, is superimposed a second mass of lava, together with tuff or peperino, In the midst of the same alternating igneous and aqueous formations is seen near Galieri, not far from Vizzini, a horizontal bed, about a foot and a half in thickness, composed entirely of a common Mediterranean coral (Caryophyllia cespitosa, Lam.). These corals stand erect as they grew ; Fig. 128. e Caryophyllia cespitosa, Lam. (Cladocora stellaria, Milne Edw. and Haime.) a. Stem with young stem growing from its side. a*, Young stem of same twice magnified. >. Portion of branch, twice magnified, with the base of a lateral branch; the exterior ridges of the main branch appearing through the lamelle of the lateral one. c, Transverse section of same, proving by the integrity of the main branch, that the lateral one did not originate in a subdivision of the animal. d. A branch, having at its base another laterally united to it, and two young corals at its upper part. é. A main branch, with a full grown lateral one, jf. A perfect terminal star. 158 NEWER PLIOCENE STRATA OF SICILY. [Cu. XII and, after being traced for hundreds of yards, are again found at a cor- responding height on the opposite side of the valley. a The corals are usually branched, but not by the division of the animals as some have supposed, but by the attachment of young individuals to the sides of the older ones; and we must understand this mode of in- crease, in order to appreciate the time which was required for the building up of the whole bed of coral during the growth of many successive gen- erations.* Among the other fossil shells met with in these Sicilian strata, which still continue to abound in the Mediterranean, no shell is more conspic- uous, from its size and frequent occurrence, than the great scallop, Pecten jacobeus (see fig. 129), now so common in the neighboring seas. We see this shell in the calcareous beds at Palermo in great numbers, in the limestone at Girgenti, and in that which alternates with voleanic rocks in the country between Syracuse and Vizzini, often at great heights above the sea. Fig. 129. . Pecten jacobeus ; half natural size. The more we reflect on the preponderating number of these recent shells, the more we are surprised at the great thickness, solidity, and height above the sea of the rocky masses in which they are entombed, and the vast amount of geographical change which has taken place since their origin. It must be remembered that, before they began to emerge, the uppermost strata of the whole must have been deposited under water. In order, therefore, to form a just conception of their antiquity, we must first examine singly the innumerable minute parts of which the whole is made up, the successive beds of shells, corals, yoleanic ashes, conglomer- ates, and sheets of lava; and we must afterwards contemplate the time * IT am indebted to Mr. Lonsdale for the details aboye given respecting the structure of this coral, Cu. XIIL] CAVE BRECCIAS. 159 required for the gradual upheaval of the rocks, and the excavation of the valleys. The historical period seems scarcely to form an appreciable unit in this computation, for we find ancient Greek temples, like those of Girgenti (Agrigentum), built of the modern limestone of which we are speaking, and resting on a hill composed of the same; the site having remained to all appearance unaltered since the Greeks first colonized the island. : The modern geological date of the rocks in this region leads to another singular and unexpected conclusion, namely, that the fauna and flora of a large part of Sicily are of higher antiquity than the country itself, having not only flourished before the lands were raised from the deep, but ever before their materials were brought together beneath the waters. The chain of reasoning which conducts us to this opinion may be stated in a few words. The larger part of the island has been converted from sea into land since the Mediterranean was peopled with nearly all the living species of testacea and zoophytes. We may therefore presume that, before this region emerged, the same land and river shells, and almost all the same animals and plants, were in existence which now people Sicily ; for the terrestrial fauna and flora of this island are pre- cisely the same as that of other lands surrounding the Mediterranean. There appear to be no peculiar or indigenous species, and those which are now established there must be supposed to have migrated from pre- existing lands, just as the plants and animals of the Neapolitan territory have colonized Monte Nuovo, since that volcanic cone was thrown up in the sixteenth century. Such conclusions throw a new light on the adaptation of the attributes and migratory habits of animals and plants to the changes which are un- ceasingly in progress in the physical geography of the globe. It is clear that the duration of species is so great, that they are destined to outlive many important revolutions in the configuration of the earth’s surface ; and hence those innumerable contrivances for enabling the subjects of the animal and vegetable creation to extend their range; the inhabitants of the land being often carried across the ocean, and the aquatic tribes over great continental spaces. It is obviously expedient that the terrestrial and fluviatile species should not only be fitted for the rivers, valleys, plains, and mountains which exist at the era of their creation, but for others that are destined to be formed before the species shall become extinct; and, in like manner, the marine species are not only made for the deep and shallow regions of the ocean existing at the time when they are called into being, but for tracts that may be submerged or variously altered in depth during the time that is allotted for their continuance on the globe. OSSEOUS BRECCIAS AND DEPOSITS IN CAVES OF THE PLIOCENE PERIOD. Sicily—Caverns filled with marine breccias, at the base of ancient sea-clifis, have been already mentioned in the sixth chapter; and it was noticed, respecting the cave of San Ciro, near Palermo (p. 75), that upon \ ¢ 160 KIRKDALE CAVE. [Cu. XIIL a bed of sand filled with sea-shells, almost all of recent species, rests a breccia (6, fig. 93), composed of fragments of calcareous rock, and the bones of animals. In the sand at the bottom of that cave, Dr. Philippi found about forty-five marine shells, all clearly identical with recent species, except two or three. The bones in the incumbent breccia are chiefly those of the mammoth (Z. primigenius), with some belonging to an hippopotamus, distinct from the recent species, and smaller than that usually found fossil. (See fig. 187.) Several species of deer also, and, according to some accounts, the remains of a bear, were discovered. These mammalia are probably referable to the Post-Pliocene period. The Newer Pliocene tertiary limestone of the south of Sicily, already described, is sometimes full of caverns: and the student will at once per- ceive that all the quadrupeds of which the remains are found in the sta- lactite of these caverns, being of later origin than the rocks, must be re- ferable to the close of the tertiary epoch, if not of still later date. The situation of one of these caves, in the valley of Sortino, is represented in the annexed section. Fig. 130. = oa TE anvonves | containing the remains of quadrupeds for the most part extinct. 2 Pe chad Ss C. Limestone containing the remains of shells, of which between 70 and 80 per cent. are recent. England.—In a cave at Kirkdale, about twenty-five miles N. N.E, of York, the remains of about 300 hyzenas, belonging to individuals of every age, have been detected. The species (Hycna spelea) is extinct, and was larger than the fierce Hyena crocuta of South Africa, which it most re- sembled. Dr. Buckland, after carefully examining the spot, proved that the Hyzenas must have lived there; a fact attested by the quantity of their dung, which, as in the case of the living hyzena, is of nearly the same composition as bone, and almost as durable. In the cave were found the remains of the ox, young elephant, hippopotamus, rhinoceros, horse, bear, wolf, hare, water-rat, and several birds. All the bones have the appear- ance of having been broken and gnawed by the teeth of the hyzenas; and they occur confusedly mixed in loam or mud, or dispersed through a crust of stalagmite which covers it. In these and many other cases it is supposed that portions of herbivorous quadrupeds have been dragged into caverns by beasts of prey, and have served as their food, an opinion quite consistent with the known habits of the living hyzena. No less than thirty-seven species of mammalia are enumerated by Pro- fessor Owen as having been discovered in the caves of the British islands, of which eighteen appear to be extinct, while the others still survive Cu. XIIL] : AUSTRALIAN CAVERNS. 161 in Europe. They were not washed to the spots where the fossils now oc- cur by a great flood ; but lived and died, one generation after another, in the places where they lie buried. Among other arguments in favor of this conclusion may be mentioned the great numbers of the shed antlers of deer discovered in cayes and in freshwater strata throughout England.* Examples also occur of fissures into which animals have fallen from time to time, or have been washed in from above, together with alluvial matter and fragments of rock detached by frost, forming a mass which may be united into a bony breccia by stalagmitic infiltrations. Fre- quently we discover a long suite of caverns connected by narrow and irregular galleries, which hold a tortuous course through the interior of mountains, and seem to have served as the subterranean channels of springs and engulfed rivers. Many streams in the Morea are now car- rying bones, pebbles, and mud into underground passages of this kind. Tf, at some future period, the form of that country should be wholly altered by subterranean movements and new valleys shaped out by denudation, many portions of the former channels of these engulfed streams may communicate with the surface, and become the dens of wild beasts, or the recesses to which quadrupeds retreat to die. Certain caves of France, Germany, and Belgium, may have passed successively through these different conditions, and in their last state may have remained open to the day for several tertiary periods. It is nevertheless re- markable, that on the continent of Europe, as in England, the fossil remains of mammalia belong almost exclusively to those of the Newer Pliocene and Post-Pliocene periods, and not to the Miocene or Eocene epochs, and when they are accompanied by land or river shells, these agree in great part, or entirely, with recent species. As the preservation of the fossil bones is due to a slow and constant supply of stalactite, brought into the caverns by water dropping from the roof, the source and origin of this deposit has been a subject of curious inguiry. The following explanation of the phenomenon has been re- cently suggested by the eminent chemist Liebig. On the surface of Franconia, where the limestone abounds in caverns, is a fertile soil, in which yegetable matter is continually decaying. This mould or humus, being acted on by moisture and air, evolves carbonic acid which is dis- solved by rain. The rain-water, thus impregnated, permeates the porous limestone, dissolves a portion of it, and afterwards, when the excess of carbonic acid evaporates in the caverns, parts with the calcareous matter, and forms stalactite. Such facts seem to imply that the date of the emer- gence of the district was very modern, for stalactite could not begin to form until the emergence of the cavernous rock, and the land shells and land animals are usually imbedded in the lowest part of the stalactite deposit. Australian cave-breccias.—Ossiferous breccias are not confined to Eu- rope, but occur in all parts of the globe; and those lately discovered in fissures and caverns in Australia correspond closely in character with what has been called the bony breccia of the Mediterranean, in which the * Owen, Brit. Foss. Mam, xxvi. and Buckland, Rel. Dil. 19, 24. 11 162 FOSSILS IN AUSTRALIAN CAVES. - (Ca. XII, fragments of bone and rock are firmly bound together by a red ochreous cement. Some of these caves have been examined by Sir T. Mitchell in the Wellington Valley, about 210 miles west of Sidney, on the river Bell, one of the principal sources of the Macquarie, and on the Macquarie itself. The caverns often branch off in different directions through the rock, widening and contracting their dimensions, and the roofs and floors are covered with stalactite. The bones are often broken, but do not seem to be water-worn. In some places they lie imbedded in loose earth, but they are usually included in a breccia. The remains found most abundantly are those of the kangaroo, of which there are four species, besides which the genera Hypsiprymnus, Phalangista, Phascolomys, and Dasyurus, occur. There are also bones, formerly conjectured by some osteologists to belong to the hippopotamus, and by others to the dugong, but which are now referred by Mr. Owen to a marsupial genus, allied to the Wombat. In the fossils above enumerated, several species are larger than the largest living ones of the same genera now known in Australia. The annexed figure of the right side of a lower jaw of a kangaroo (Maero- Macropus atlas, Owen. a, Permanent false molar, in the alveolus. * pus atlas, Owen) will at once be seen to exceed in magnitude the cor- responding part of the largest living kangaroo, which is represented in Fig. 132. Lowest jaw of largest living species of kangaroo. (Macropus major.) Cu. XIII] EXTINCT FOSSIL MAMMALIA, 163 fig. 132. In both these specimens part of the substance of the jaw has been broker open, so as to show the permanent false molar (a, fig. 131) concealed in the socket. From the fact of this molar not having been cut, we learn that the individual was young, and had not shed its first teeth. In fig. 133, a front tooth of the same species of kangaroo, is represented. Whether the breccias, above alluded to, of the Wellington Valley, appertain strictly to the Pliocene period cannot be affirmed with certainty, until we are more thoroughly acquainted with the recent quadrupeds of the same dis- trict, and until we learn what species of fossil land shells, if any, are buried in the deposits of the same caves. The reader will observe that all these extinct quadrupeds of Australia belong to the marsupial family, or, in other words, that they are referable to the same peculiar type of m/f organization which now distinguishes the Australian mam- Incisor of Ma. ‘Malia from those of other parts of the globe. This fact is cropus. one of many pointing to a general law deducible from the fossil vertebrate and invertebrate animals of the eras immediately ante- cedent to the human, namely, that the present geographical distribution of organic forms dates back to a period anterior to the creation of ex- isting species ; in other words, the limitation of particular genera or families of quadrupeds, mollusca, &ec., to certain existing provinces of land and sea, began before the species now contemporary with man had been introduced into the earth. Mr. Owen, in his excellent “ History of British Fossil Mammals,” has called attention to this law, remarking that the fossil quadrupeds of Europe and Asia differ from those of Australia or South America. We do not find, for example, in the Europzo-Asiatic province fossil kangaroos or armadillos, but the elephant, rhinoceros, horse, bear, hyzna, beaver, hare, mele, and others, which still characterize the same continent. In like manner in the Pampas of South America the skeletons of Me- gatherium, Megalonyx, Glyptodon, Mylodon, Toxodon, Macrauchenia, and other extinct forms, are analogous to the living sloth, armadillo, cavy, capybara, and llama. The fossil quadrumana, also associated with some of these forms in the Brazilian caves, belong to the Platyrrhine family of monkeys, now peculiar to South America. That the extinct fauna of Buenos Ayres and Brazil was very modern has been shown by its rela- tion to deposits of marine shells, agreeing with those now inhabiting the Atlantic; and when in Georgia in 1845, I ascertained that the Mega- therium, Mylodon, Harlanus americanus (Owen), Hquus curvidens, and other quadrupeds allied to the Pampean type, were posterior in date to beds containing marine shells belonging to forty-five recent species of the neighboring sea. There are indeed some cosmopolite genera, such as the Mastodon (a genus of the elephant family), and the horse, which were simultaneously represented by different fossil species in Europe, North America, and 164 EXTINCT FOSSIL MAMMALIA. (Ca. XTIL South America; but these few exceptions can by no means invalidate the rule which has been thus expressed by Professor Owen, “ that in the highest organized class of animals the same forms were restricted to the same great provinces at the Pliocene periods as they are at the pres- ent day.” However modern, in a geological point of view, we may consider the Pleistocene epoch, it is evident that causes more general and powerful than the intervention of man have occasioned the disappearance of the ancient fauna from so many extensive regions. Not a few of the species had a wide range; the same Megatherium, for instance, extended from Patagonia and the river Plata in South America, between latitudes 31° and 39° south, to corresponding latitudes in North America, the same animal being also an inhabitant of the intermediate country of Brazil, where its fossil remains have been met with in caves. The extinct ele- phant, likewise, of Georgia (Hlephas primigenius) has been traced in a fossil state northward from the river Alatamaha, in lat. 33° 50’ N. to the polar regions, and then again in the eastern hemisphere from Siberia to the south of Europe. If it be objected that, notwithstanding the adapta- tion of such quadrupeds to a variety of climates and geographical con- ditions, their great size exposed them to extermination by the first hunter tribes, we may observe that the investigations of Lund and Clausen in the ossiferous limestone caves of Brazil have demonstrated that these large mammalia were associated with a great many smaller quadrupeds, some of them as diminutive as field mice, which have all died out together, while the land shells formerly their contemporaries still continue to exist in the same countries. As we may feel assured that these minute quad- rupeds could never have been extirpated by man, especially in a country so thinly peopled as Brazil, so we may conclude that all the species, small and great, have been annihilated one after the other, in the course of in- definite ages, by those changes of circumstances in the organic and inor- ganie world which are always in progress, and are capable in the course of time of greatly modifying the physical geography, climate, and all other conditions on which the continuance upon the earth of any living being must depend.* The law of geographical relationship above alluded to, between the living vertebrata of every great zoological province and the fossils of the period immediately antecedent, even where the fossil species are extinct, is by no means confined to the mammalia. New Zealand, when first examined by Europeans, was found to contain no indigenous Jand quad- rupeds, no kangaroos, or opossums, like Australia; but a wingless bird abounded there, the smallest living representative of the ostrich family, called Kivi, by the natives (Apteryzx). In the fossils of the Post-Phocene and Pleistocene period in this same island, there is the like absence of kangaroos, opossums, wombats, and the rest; but in their place a pro- digious number of well-preserved specimens of. gigantic birds of the stru- thious order, called by Owen Dinornis and Palapteryz, which are en- * See Principles of Geology, chaps. xli. to xliv. Cx. XIIL] TEETH OF FOSSIL QUADRUPEDS. 165 tombed in superficial deposits. These genera comprehended many spe- cies, some of which were 4, some 7, others 9, and others 11 feet in height! It seems doubtful whether any contemporary mammalia shared the land with this population of gigantic feathered bipeds. To those who have never studied comparative anatomy it may seem searcely credible, that a single bone taken from any part of the skeleton may enable a skilful osteologist to distinguish, in many cases, the genus, and sometimes the species, of quadruped to which it belonged. Although few geologists can aspire to such knowledge, which must be the result of long practice and study, they will nevertheless derive great advantage from learning what is comparatively an easy task, to distinguish the principal divisions of the mammalia by the forms and characters of their teeth. The annexed figures, all taken from original specimens, may be useful in assisting the student to recognize the teeth of many genera most frequently found fossil in the Newer Pliocene and Post-Pliocene periods :— Fig. 134. Elephas primigenius (or Mammoth); molar of upper jaw, right side; one-third of nat. size, a. Grinding surface. 6. Side view. Mastodon arvernensis (Norwich Crag, Postwick, also found in Red Crag, see p. 155); second true molar, left side, upper jaw; grinding surface, nat. size. (See, p. 155.) 166 TEETH OF FOSSIL MAMMALIA, [Cu. XIIL Fig. 136. Fig. 187. Fiz. 188, Rhinoceros, Hippopotamus. Pig. Rhinoceros leptorhinus; fose Hippopotamus Pentiandi, Sus scrofa, Lin. (common sil from freshwater beds of H. y. Meyer; from cave ig); from shell-marl, Grays, Essex (see p. 153); near Palermo (see p: 160); ‘orfarshire ; posterior penultimate molar, lower molar tooth; two-thirds molar, lower jaw, bat jaw, left side; two-thirds of of nat. size. size. nat. size. Fig. 189. Tapir. Tapirus Americanus ; recent; third molar, upper jaw; nat. size. Horse. Equus cadailus, Lin. (common horse); from the shell-marl, Forfarshire ; second molar, lower jaw. a, Grinding surface, two-thirds nat. size. b. Side view of same, half nat. size. Fig. 141. a, 6. Deer. ce. d, Ox. Elk (Cervus alces, Lin.); re- Os, common, from shell-marl, Forfar- cent; molar of upper jaw. shire ; tree molar upper jaw; two- a. Grinding surface. thirds nat. size. vb. Side view; two-thirds of e. Grinding surface. nat. size, d. Side view ; fangs uppermost. Cu. XIV] OLDER PLIOCENE FORMATIONS. 167 Fig. 143. Fig. 144. Bear. Tiger. @, Canine tooth or tusk of bear ( Ursus e. Canine tooth of tiger (Felis tigris) ; speleus); from cave near Liege. recent, — ‘ 6. Molar of left side, upper jaw; one d, Outside view of posterior molar third of nat. size. lower jaw; one-third of nat. size. Fig, 146, Hyena epelea: second molar,left Teeth of a new species of Arvicola (field mouse); from the side, lower jaw; nat. size. Cave Norwich Crag. (See p. 155.) of Kirkdale, (See p. 160.) a. Grinding surface. b. Side view of same. c. Nat. size of a and b. Fig. 147, a, Fourth molar, right side, lower jaw. Jfegatherium; Georgia, b. Crown of same. U. 5.; one-third nat, size. CHAPTER XIV. OLDER PLIOCENE AND MIOCENE FORMATIONS. Strata of Suffolk termed Red and Coralline Crag—Fossils, and proportion of re- cent species—Depth of sea and climate—Reference of Suffolk Crag to the Older Pliocene period—Migration of many species of shélls southwards during the glacial period—Fossil whales—Antwerp Crag—Subapennine beds—Asti, Sienna, Rome— Aralo-Caspian formations — Miocene formations — Faluns of Touraine-—Depth of sea and littoral character of fauna—Tropical climate im. plied by the testacea—Proportion of recent species of shells—Faluns more an- cient than the Suffolk Crag—Miocene strata of Bourdeaux—of the Bolderberg in Belgium—of North Germany—Vienna Basin—Piedmont—Molasse of Swit- zerland—Leaf-beds of Mull in Scotland—Older Pliocene and Miocene forma- tions in the United States—Sewalik Hills in India. Tue older Pliocene strata, which next claim our attention, are chiefly confined, in Great Britain, to the eastern part of the county of Suffolk, 168 OLDER PLIOCENE FORMATIONS. [Cu. XIV where, like the Norwich beds already described, they are called “ Crag,” a provincial name given particularly to those masses of shelly sand which have been used from very ancient times in agriculture, to fertilize soils deficient in calcareous matter. The relative position of the “ Red Crag” in Essex to the London clay, may be understood by reference to the ac- companying diagram (fig. 148). Fig. 148. Crag. London Clay. Chalk. . 3 These deposits, according to Professor E. Forbes, appear by their im- bedded shells to have been formed in a sea of moderate depth, usually from 15 to 25 fathoms, but in some few spots perhaps deeper. Yet they cannot be called littoral, because the fauna is such as may have extended . 40 or 50 miles from land. The Suffolk Crag is divisible into two masses, the upper of which has been termed the Red, and the lower the Coralline Crag.* The upper deposit consists chiefly of quartzose sand, with an occasional, intermixture of shells, for the most part rolled, and sometimes comminuted. In many places fossils washed out of older tertiary strata, especially the London Clay, are met with. The lower or coralline Crag is of very limited ex- tent, ranging over an area about 20 miles in length, and 3 or 4 in breadth, between the rivers Alde and Stour. It is generally calcareous and marly —a mass of shells, bryozoa,t and small corals, passing occasionally into a soft building-stone. At Sudbourn, near Oxford, where it assumes this character, are large quarries, in which the bottom of it has not been reached at the depth of 50 feet. At some places in the neighborhood, the softer mass is divided by thin flags of hard limestone, and corals placed in the upright position in which they grew. The Red Crag is distinguished by the deep ferruginous or ochreous color of its sands and fossils, the Coralline by its white color. Both for- mations are of moderate thickness; the Red Crag rarely exceeding 40, and the Coralline seldom amounting to 20 feet. But their importance is not to be estimated by the density of the mass of strata or its geographical extent, but by the extraordinary richness of its organic remains, belonging * See paper by E. Charlesworth, Esq.; London and Ed. Phil. Mag. No. xxxviii. p- 81, Aug. 1835. + Ehrenberg proposed in 1831 the term Bryozoum, or “ Moss-animal,” for the molluscous or ascidian form of polyp, characterized by having two openings to the digestive sack, as in Eschara, Flustra, Retepora, and other zoophytes popu- larly included in the corals, but now classed by naturalists as mollusea. The term Polyzoum, synonymous with Bryozowm, was, it seems, proposed in 1830, or the year before, by Mr. J. V. Thompson, but is less generally adopted. The ani- mals of the Zoantharia of Milne Edwards and Haime, or the true corals, have only one opening to the stomach. Cu. XIV.] SUFFOLK CRAG.: 169 to a very peculiar type, which seems to characterize the state of the living creation in the north of Europe during the Older Pliocene era. For a large collection of the fish, echinoderms, shells, bryozoa, and cor- als of the deposits in Suffolk, we are indebted to the labors of Mr. Searles Wood. Of testacea alone he has obtained 230 species from the Red, and 845 from the Coralline Crag, about 150 being common to each. The proportion of recent species in the new group is considered by Mr. Wood to be about 70* per cent., and that in the older or Coralline about 60. When I examined these shells of Suffolk in 1835, with the assistance of Dr. Beck, Mr. George Sowerby, Mr. Searles Wood, and other eminent conchologists, I came to the opinion that the extinct species predominated very decidedly in number over the living. Recent investigations, how- ever, have thrown much new light on the conchology of the Arctic, Scandinavian, British, and Mediterranean Seas. Many of the species for- merly known only as fossils of the Crag, and supposed to have died out, have been dredged up in a living state from depths not previously ex- plored. Other recent species, before regarded as distinct from the nearest allied Crag fossils, have been observed, when numerous individuals were procured, to be liable to much greater variation, both in size and form, than had been suspected, and thus have been identified. Consequently, the Crag fauna has been found to approach much more nearly to the re- cent fauna of the Northern, British, and Mediterranean Seas than had been imagined. The analogy of the whole group of testacea to the Eu- ropean type is very marked, whether we refer to the large development. . of certain genera in number of species or to their size, or to the sup- pression or feeble representation of others. The indication also afforded _ by the entire fauna of a climate not much warmer than that now pre- vailing in corresponding latitudes, prepares us to believe that they are not of higher antiquity than the Older Pliocene era. The position of the Red Crag in Essex to the subjacent London clay and chalk has been already pointed out (fig. 148). Whenever the two divisions are met with in the same district, the Red Crag lies uppermost ; and, in some cases, as in the section represented in fig. 149, which I had an opportunity of seeing exposed to view in 1839, it is clear that the older or Coralline mass 6 had suffered denudation, before the newer for- mation @ was thrown down upon it. At D there is not only a distinct Fig. 149. Shottisham Sutton. Creek. Ramsholt. Section near Ipswich, in Suffolk. a, Red Crag. 6. Coralline Crag, c. London Clay. cliff, 8 or 10 feet high, of Coralline Crag, running in a direction N. E. and S. W., against which the red crag abuts with its horizontal layers; but * See Monograph on the Crag Mollusca, Searles Wood, Paleont. Soc. 1848. 170 OLDER PLIOCENE FORMATIONS. [Cu XIV. this cliff occasionally overhangs. The rock composing it is drilled every- where by Pholades, the holes which they perforated having been after wards filled with sand and covered over when the newer beds were thrown down. As the older formation is shown by its fossils to have accumulated in a deeper sea (15, and sometimes 25, fathoms deep or more), there must no doubt have been an upheaval of the sea-bottom before the cliff here alluded to was shaped out. We may also conclude that so great an amount of denudation could scarcely take place, in such incoherent ma- terials, without many of the fossils of the inferior beds becoming mixed up with the overlying crag, so that considerable difficulty must be occasion- ally experienced by the paleontologists in deciding which species belong severally to each group. The Red Crag being formed in a shallower sea, often resembles in struc- ture a shifting sand-bank, its layers being inclined diagonally, and the planes of stratification being sometimes directed in the same quarry to the four cardinal points of the compass, as at Butley. That in this and many other localities, such a structure is not deceptive or due to any sub- sequent concretionary rearrangement of particles, or to mere lines of color, is proved by each bed being made up of flat pieces of shell which lie par- allel to the planes of the smaller strata. Some fossils, which are very abundant in the Red Crag, have never been found in the white or coralline division ; as, for example, the Fusus contrarius (fig. 150), and several species of Murex and Buccinum (or Nassa) (see figs. 151, 152), which two genera seem wanting in the lower crag. Fossils characteristic of the Red Crag. Fig. 151, Fig. 153. Fusus contrarius. Murex alveotatus. Cyprea coccinelloides, Fig. 150 half nat. size; the others nat. size. Among the bones and teeth of fishes are those of large sharks (Carcha- rodon), and a gigantic skate of the extinct genus Vyliobates, and many other forms, some common to our seas, and many foreign to them. It is questionable, however, whether all these can really be ascribed to the era of the Red Crag. Not a few of them may possibly haye been derived from older strata, especially from those Upper Eocene formations to be described in the next chapter, which are largely developed in Belgium, Cx. XIV.] FOSSILS OF THE SUFFOLK CRAG. 171 and of which a fragment (the Hempstead beds of Forbes) escaped denu- dation in England. The distinctness of the fossils of the Coralline from those of the Red Crag, arises in part from their higher antiquity, and, in some degree, from a difference in the geographical conditions of the submarine bottom. The prolific growth of corals, echini, and a prodigious variety of testacea and bryozoa, implies a region of deeper and more tranquil water; whereas, ~ the Red Crag may have been formed afterwards on the same spot, when the water was shallower. In the mean time the climate may have become somewhat cooler, and some of the zoophytes which flourished in the first period may have disappeared, so that the fauna of the Red Crag acquired a character somewhat more nearly resembling that of our northern seas, as is implied by the large development of certain sections of the genera Fusus, Buccinum, Purpura, and Trochus, proper to higher latitudes, and which are wanting or feebly represented in the inferior crag. Some of the corals and bryozoa of the lower Crag of Suffolk belong to genera unknown in the living creation, and of a very peculiar ‘structure ; as, for example, that represented in the annexed fig. (154), which is one Family, Tubwliporide, of same author. Bryozoan of extinct genus, from the inferior or Coralline Crag, Suffolk. a, Exterior. 6. Vertical section of interior. ec. Portion of exterior magnified. d. Portion of interior magnified, showing that it is made up of long, thin, straight tubes, united in conical bundles, of seyeral species haying a globular form. The great number and variety of these zoophytes probably indicate an equable climate, free from intense cold in winter. On the other hand, that the heat was never excessive is confirmed by the prevalence of northern forms among the testacea, such as the Glycimeris, Cyprina, and Astarte. Of the genus last mentioned (see fig. 155) there are about fourteen species, many of them being rich in individuals; and there is an absence of genera peculiar to hot climates, such as Conus, Oliva, Mitra, Fasciolaria, Crassatella, and others. The cowries ( Cypreea, fig. 158), also, are small, and belong to a section (Z’rivia) now inhabiting the colder regions, A large volute, called Voluta Lam- berti (fig. 156), may seem an exception; but it differs in form from the 172 OLDER PLIOCENE FORMATIONS. [Cu. XIV. Fig. 155. Astarte Omalii, Lajonkaire; Syn. A. bipartita, Sow. Min. Con. T. 521, f. 8; a very variable species, most characteristic of the Coralline Crag, Suffolk. volutes of the torrid zone, and may, like the living Voluta Magellanica, have been fitted for an extra-tropical climate. Fig, 156. Fig. 157. Fig. 158. Voluta Lamberti, young Pyrula reticulata, Lam. ; Temnechinus excavatus, individ., Cor. and Red Coralline Crag, Ram- Forbes; Temnopleurus Crag. sholt. excavatus, Wood; Cor. Crag, Ramsholt. The occurrence of a species of Zingula at Sutton (see fig. 160) is worthy of remark, as these Brachiopoda seem now confined to more equatorial latitudes ; and the same may be said still more decidedly of a species of Pyrula, supposed by Mr. Wood to be identical with P. reticulata (fig. 157), now living in the Indian Ocean. A genus also of echinoderms, called by Professor Forbes Temnechinus (fig. 158), is peculiar to the Red and Coralline Crag of Suffolk. The only species now living occur in the Indian Ocean. Whether, therefore, we may incline to the belief that the mean annual temperature was higher or lower than now, we may at least infer that the climate and geographical conditions were by no means the same at the period of the Suffolk Crag as those which now prevail in the same region. One of the most interesting conclusions deduced from a careful com- parison of the shells of these British Older Pliocene strata and the fauna of our present seas, has been pointed out by Prof. E. Forbes. It appears that, during the glacial period, a period intermediate, as we have seen, between that of the crag and our own time, many shells, previously estab- lished in the temperate zone, retreated southwards to avoid an uncon- genial climate. The Professor has given a list of fifty shells which in- habited the British seas while the Coralline and Red Crag were forming, Cu. XIV.] SUBAPENNINE STRATA. 173 and which, though now living in our seas, are all wanting in the Pleisto- cene or glacial deposits. They must therefore, after their migration to the south, which took place during the glacial period, have made their way northwards again. In corroboration of these views, it is stated that all these fifty species occur fossil in the Newer Pliocene strata of Sicily, Southern Italy, and the Grecian Archipelago, where they may have en- joyed, during the era of floating icebergs, a climate resembling that now prevailing in higher European latitudes.* In the Red Crag at Felixstow, in Suffolk, Professor Henslow has found the ear-bones of one or more species of cetacea, which, according to Prof. Owen, are the remains of true whales of the family Balenide (fig. 159). Mr. Wood is of opinion that these cetacea may be of the age of the Red Crag, or if not, that they may be derived from the destruct’on of beds of Coralline Crag. Antwerp.—Strata of the same age as the Red and Coralline Crag of Suffolk have been long known in the country round Antwerp and on the banks of the Scheldt, below that city. More than 200 species of testacea Fig. 159. Fig. 160, Tympanic bone of Balena emarginata, Lingula Dumortieri, Nyst; Owen; Red Crag, Felixstow. Antwerp Crag. have been collected by MM. De Wael, Nyst, and others, of which two- thirds haye been identified with Suffolk fossils by Mr. Wood. Among these he recognizes Lingula Dumortiert of Nyst (fig. 160), which I found in abundance at Antwerp in 1851, in what is called by M. de Wael the middle crag. More than half of the shells of this Antwerp deposit agree with living species, and these belong in great part to the fauna of our northern seas, though some Mediterranean species are not wanting. I also met with numerous cetacean bones of the genera Balenoptera and Ziphius in the same formation. They are not at all rolled, as if washed out of older beds, and I infer that the animals to which they belonged once coexisted in the same sea with the associated mollusca.t Normandy.—I observed in 1840 a small patch of shells corresponding to those of the Suffolk Crag, near Valognes, in Normandy ; and there is a deposit containing similar fossils at St. George Bohon, and several places a few leagues to the S. of Carentan, in Normandy; but they have never been traced farther southwards. Subapennine strata—The Apennines, it is well known, are composed chiefly of secondary rocks, forming a chain which branches off from the Ligurian Alps and passes down the middle of the Italian peninsula. At * E. Forbes, Mem. Geol. Survey, Gt. Brit. vol. i. 386. + Lyell on Belgian Tertiaries, Quart. Journ. Geol. Soc. 1852, p. 882. 174 SUBAPENNINE STRATA. [Cu. XIV. the foot of these mountains, on the side both of the Adriatic and the Mediterranean, are found a series of tertiary strata, which form, for the most part, a line of low hills occupying the space between the older chain and the sea. Brocchi, as we have seen (p. 110), was the first Italian | geologist who described this newer group in detail, giving it the name of the Subapennines; and he classed all the tertiary strata of Italy, from Piedmont to Calabria, as parts of the same system. Certain mineral characters, he observed, were common to the whole; for the strata consist generally of light brown or blue marl, covered by yellow calcareous sand and gravel. There are also, he added, some species of fossil shells which are found in these deposits throughout the whole of Italy. We have now, however, satisfactory evidence that the Subapennine beds of Brocchi, although chiefly composed of Older Pliocene strata, be- long nevertheless, in part, both to older and newer members of the ter- tiary series. The strata, for example, of the Superga, near Turin, are Miocene; those of Asti and Parma, Older Pliocene, as is the blue marl of Sienna; while the shells of the incumbent yellow sand of the same ter- ritory approach more nearly to the recent fauna of the Mediterranean, and may be Newer Pliocene. The grayish-brown or blue marl of the Subapennine formation is very aluminous, and usually contains much calcareous matter and scales of mica. Near Parma it attains a thickness of 2000 feet, and is charged throughout with marine shells, some of which lived in deep, others in shallow water, while a few belong to freshwater genera, and must have been washed in by rivers. Among these last I have seen the common Limnea palustris in the blue marl, filled with small marine shells. The wood and leaves, which occasionally formed beds of lignite in the same deposit, may have been carried into the sea by similar causes. The shells, in general, are soft when first taken from the marl, but they become hard when dried. The superficial enamel is often well preserved, and many shells retain their pearly lustre, part of their external color, and even the ligament which unites the valves. No shells are more usually perfect than the microscopic foraminifera, which abound near Sienna, where more than a thousand full-grown individuals may be sometimes poured out of the interior of a single univalve of moderate dimensions. The other member of the Subapennine group, the yellow sand and con- glomerate, constitutes, in most places, a border formation near the junction of the tertiary and secondary rocks. In some cases, as nearsthe town of Sienna, we see sand and calcareous gravel resting immediately on the Apennine limestone, without the intervention of any blue marl. Alterna- tions are there seen of beds containing fluviatile shells, with others filled exclusively with marine species; and I observed oysters attached to many limestone pebbles. The site of Sienna appears to have been a point where a river, flowing from the Apennines, entered the sea when the tertiary strata were formed. The sand passes in some.districts into a calcareous sandstone, as at San Vignone. Its general superposition to the marl, even in parts of Italy Cu. XIV.] MIOCENE FORMATIONS. 175 and Sicily where the date of its origin is very distinct, may be explained if we consider that it may represent the deltas of rivers and torrents, which gained upon the bed of the sea where blue marl had previously been de- posited. The latter, being composed of the finer and more transportable mud, would be conveyed to a distance, and first occupy the bottom, over which sand and pebbles would afterwards be spread, in proportion as rivers pushed their deltas farther outwards. In some large tracts of yel- low sand it is impossible to detect a single fossil, while in other places they occur in profusion. Occasionally the shells are silicified, as at San Vitale, near Parma, from whence I saw two individuals of recent species, one freshwater and the other marine (Lymnea palustris, and Cytherea concentrica, Lam.), both perfectly converted into flint. Rome.—the seven hills of Rome are composed jartly of marine ter- tiary strata, those of Monte Mario, for example, of the Older Pliocene period, and partly of superimposed volcanic tuff, on the top of which are usually cappings of a fluviatile and lacustrine deposit. Thus, on Mount Aventine, the Vatican, and the Capitol, we find beds of calcareous tufa with incrusted reeds, and recent terrestrial shells, at the height of about 200 feet above the alluvial plain of the Tiber. The tusk of the mammoth has been procured from this formation, but the shells appear to be all of living species, and must have been imbedded when the summit of the Capitol was a marsh, and constituted one of the lowest hollows of the country as it then existed. It is not without interest that we thus dis- cover the extremely recent date of a geological event which preceded an historical era so remote as the building of Rome. Aralo-Caspian formations—This name has been given by Sir R. Mur- chison and M. de Verneuil to the limestone and associated sandy beds, of brackish-water origin, which have been traced over a very extensive area surrounding the Caspian, Azoff, and Aral Seas, and parts of the northern and western coasts of the Black Sea. The fossil shells are partly fresh- water, as Paludina, Neritina, &c., and partly marine, of the family Car- discie and Mytili. The species are identical, in great part, with those now inhabiting the Caspian ; and when not living, they are analogous to forms now found in the inland seas of Asia, rather than to oceanic types. The limestone rises occasionally to the height of several hundred feet above the sea, and is supposed to indicate the former existence of a vast inland sheet of brackish water as large as the Mediterranean, or larger. The proportion of recent species agreeing with the fauna of the Caspian is so considerable as to leave no doubt in the minds of the geologists above cited, that this rock, also called by them the “Steppe Limestone,” belongs to the Pliocene period.* MIOCENE FORMATIONS. Faluns of Touraine—The strata which we meet with next in the de- scending order are those called by many geologists “ Middle Tertiary,” * Geol. of Russia, p. 279, dc, 176 FALUNS OF TOURAINE. [Cx. XIV. and for which in 1838 I proposed the name of Miocene, selecting the faluns of the valley of the Loire in France as my example or type. ‘No strata contemporaneous with these formations have as yet been met with in the British, Isles, where the lower crag of Suffolk is the deposit nearest in age. The term “faluns” is given provincially by French agriculturists to shelly sand and marl spread over the land in Touraine, just as the “crag” was formerly much used to fertilize the soil in Suffolk. Isolated masses of such faluns occur from near the mouth of the Loire, in the neighborhood of Nantes, to as far inland as a district south of Tours. They are also found at Pontlevoy, on the Cher, about 70 miles above the junction of that river with the Loire, and 30 miles S. E. of Tours. De- posits of the same age also appear under new mineral conditions near the towns of Dinan and Rennes, in Brittany. I have visited all the locali- ties above enumerated, and found the beds on the Loire to consist princi- pally of sand and marl, in which are shells and corals, some entire, some rolled, and others in minute fragments. In certain districts, as at Doué, in the department of Maine and Loire, 10 miles S. W. of Saumur, they form a soft building-stone, chiefly composed of an aggregate of broken shells, bryozoa, corals, and echinoderms, united by a calcareous cement ; the whole mass being very like the Coralline Crag near Aldborough and Sudbourn in Suffolk. The scattered patches of faluns are of slight thickness, rarely exceeding 50 feet; and between the district called Sologne and the sea they repose on a great variety of older rocks; being seen to rest successively upon gneiss, clayslate, various secondary for- mations, including the chalk; and, lastly, upon the upper freshwater limestone of the Parisian tertiary series, which, as before mentioned (p. 111), stretches continuously from the basin of the Seine to that of the Loire. At some points, as at Louans, south of Tours, the shells are stained of a ferruginous color, not unlike that of the Red Crag of Suffolk. The species are, for the most part, marine, but Fig. 161. a few of them belong to land and fluviatile genera. Among the former, Helix turo- nensis (fig. 45, p. 30) is the most abun- dant. Remains of terrestrial quadrupeds are here and there intermixed, belonging to the genera Deinotherium (fig. 161), Mastodon, Khinoceros, Hippopotamus, Cheeropotamus, Dichobune, Deer, and others, and these are accompanied by cetacea, such as the Lamantine, Morse, Sea-Calf, and Dolphin, all of extinct species. Deinotherium gigantewm, Kaup. Professor E.-Forbes, after studying the fossil testacea which I obtained from these beds, informs me that he has no doubt they were formed partly on the shore itself at the level of low water, and partly at very moderate depths, not exceeding ten fathoms below that level. The mol- @s. XIV.] COMPARISON OF THE CRAG AND FALUNS. 17% luscous fauna of the “faluns” is on the whole much more littoral than that of the Red and Coralline Crag of Suffolk, and implies a shallower sea. It is, moreover, contrasted with the Suffolk Crag by the indications it affords of an extra-European climate. Thus it contains seven species of Cyprea, some larger than any existing cowry of the Mediterranean, sev- eral species of Oliva, Ancillaria, Mitra, Terebra, Pyrula, Fasciolaria, and Conus. Of the cones there are no less than eight species, some very large, whereas the only European cone is of diminutive size. The genus Werita, and many others, are also represented by individuals of a type now characteristic of equatorial seas, and wholly unlike any Mediterranean forms. These proofs of a more elevated temperature seem to imply the higher antiquity of the faluns as compared with the Suffolk Crag, and are in perfect accordance with the fact of the smaller proportion of testacea of recent species found in the faluns. Out of 290 species of shells, collected by myself in 1840 at Pontlevoy, * Louans, Bossée, and other villages twenty miles south of Tours; and at Sayigné, about fifteen miles northwest of that place, seventy-two only could be identified with recent species, which is in the proportion of twenty-five-per cent. A large number of the 290 species are common to all the localities, those peculiar to each not being more numerous than we might expect to find in different bays of the same sea. The total number of testaceous mollusca from the faluns, in my. pos- session, is 302; of which forty-five only were found by Mr. Wood t6 be common to the Suffolk Crag. The number of corals, including bryozoa and zoantharia, obtained by me at Doué, and other localities before ad- verted to, amounts to forty-three, as determined by Mr. Lonsdale, of which seven (one of them a zoantharian) agree specifically with those of the Suf- folk Crag. Only one has, as yet, been identified with a living species. But it is difficult, notwithstanding the advances recently made by MM. Dana, Milne Edwards, Haime, and Lonsdale, to institute a satisfactory comparison between recent and fossil zoantharia and bryozoa. Some of the genera occurring fossil in Touraine, as the Astrea, Dendrophyllia, Lunu- lites, have not been found in European seas north of the Mediterranean ; nevertheless the zoantharia of the faluns do not seem to indicate on the whole so warm a climate as would be inferred from the shells. It was stated that, on comparing about 300 species of Touraine shells with about 450 from the Suffolk Crag, forty-five only were found to be common to both, which is in the proportion of only fifteen per cent. The same small amount of agreement is found in the corals also. I for- merly endeayored to reconcile this marked difference in species with the supposed coexistence of the two faunas, by imagining them to have sever- ally belonged to distinct zoological provinces or two seas, the one opening to the north, and the other to the south, with a barrier of land between them, like the Isthmus of Suez, separating the Red Sea and the Medi- terranean. But I now abandon that idea for several reasons; among others, because I succeeded in 1841 in tracing the Crag fauna southwards in Normandy to within seventy miles of the Falunian type, near Dinan, 12 178 SHELLS IN MIOCENE STRATA. (Ca. XIV yet found that both assemblages of fossils retained their distinctive char- acters, showing no signs of any blending of species or transition of cli- mate. On a comparison of 280 Mediterranean shells with 600 British species, made for me by an experienced conchologist in 1841, 160 were found to be common to both collections, which is in the proportion of fifty-seven per cent., a fourfold greater specific resemblance than between the seas of the crag and the faluns, notwithstanding the greater geographical dis- tance between England and the Mediterranean than between Suffolk and the Loire. The principal grounds, however, for referring the English crag to the Older Pliocene and the French faluns to the Miocene epochs, con- sist in the predominance of fossil shells in the British strata identifiable with species, not only still living, but which are now inhabitants of neigh- boring seas, while the accompanying extinct species are of genera such as characterize Europe. In the faluns, on the contrary, the recent species are in a decided minority ; and most of them are now inhabitants of the Mediterranean, the coast of Africa, and the Indian Ocean; in a word, less northern in character and pointing to the prevalence of a warmer climate. They indicate a state of things receding farther from the present condition of central Europe in physical geography and climate, and doubtless therefore receding farther from our era in time. Bourdeaux.—A great extent of country between the Pyrenees and the Gironde is overspread by tertiary deposits of various ages from the Eocene to the Pliocene. Among these, especially near Saucats in the environs — of Bourdeaux, and at Mérignac and Bazas in the same region, are sands containing marine shells, and corals of the type of the Touraine faluns.* Belgium—In a small hill or ridge called the Bolderberg, which I visited in 1851, situated near Hasselt, about forty miles E. N. E. of Brus- sels, strata of sand and gravel occur, to which M. Dumont first called ‘attention as appearing to constitute a northern representative of the faluns of Touraine. They are quite distinct in their fossils from the Antwerp Crag before mentioned, and contain shells of the genera Oliva, Conus, Ancillaria, Pleurotoma, and Cancellaria in abun- Fig. 162, dance. The most common shell is an Olive (see fig. 162), called by Nyst Oliva Dufresnii, Bast. ; but which is undoubtedly, as M. Bosquet observes, smaller and shorter than the Bourdeaux species.+ North Germany.—We learn from the able trea- tise published by M. Beyrich, in 1853, that the fossil fauna above alluded to, which is so meagerly POS, Gin, tom, Bolder exhibited in the Bolderberg, is rich in species in @ front view; 0, back view. other localities in North Germany, as in Mecklenburg, Liineburg, the * See a Memoir by V. Raulin, 1848: Bourdeaux. + Lyell on Belgian Tertiaries, Quart. Geol. Journ. 1852, p. 295. Nyst’s figure ‘seems to be copied from that given by Basterot of the Bourdeaux fossil. ¢ Die Conchylien des Norddeutschen Tertiargebirge : Berlin, 1852. Cx. XIV.] SHELLS IN MIOCENE STRATA. 179 Island Sylt, and at Bersenbriick north of Osnabriick, in Westphalia, where it was first discovered by F. Rémer. It is also said to occur at Bocholt, and other points in Westphalia; on the borders of Holland ; also at Crefeld and Dusseldorf. Not having visited these localities, I can offer no opinion as to the agreement in age of the several deposits here enumerated. Vienna basen.—In South Germany the general resemblance of the shells of the Vienna tertiary basin with those of the faluns of Touraine has long been acknowledged. In Dr. Hornes’ excellent work, recently commenced, on the facil mollusca of that formation, we see Gems: of many shells of the genus Conus, some of large size, clearly of the same species as those found in the falunian sands of Touraine. M. Alcide @Orbigny has also shown that the foraminifera of the Vienna basin differ alike from the Eocene and Pliocene species, and agree with those of the faluns, so far as the latter are known. Among the Vienna foraminifera, the genus Amphistegina (fig. 163) is very characteristic, and is supposed Fig, 168. Amphistegina Hauerina, D’Orb. Vienna, miocene strata, by Archiac to take the same place among the foraminifera of the Miocene era, which the Nummulites occupy in the Eocene period. The Vienna basin is thought by some geologists to comprise tertiary strata of more than one age, the lowest strata reached in boring Artesian wells being older than the faluns. Piedmont.— Switzerland.—To the same Miocene or “ falunian” epoch, we may refer a portion of the strata of the Hill of the Superga near Turin in Piedmont,* as also part of the Molasse of Switzerland, or the greenish sand which fills the great Swiss valley between the Alps and the Jura. At the foot of the Alps it usually takes the form of a conglomerate called provincially “ nagelflue,” sometimes attaining the truly wonderful thickness of 6000 and 8000 feet, as in the Riga near Lucerne and in the Speer near Wesen. The lower portion of this molasse is of freshwater origin. Scotland.—Isle of Mulil—tn the sea-cliffs forming the headland of Ardtun on the west coast of Mull, in the Hebrides, several bands of ter- tiary strata containing leaves of dicotyledonous plants were discovered in 1851 by the Duke of Argyle+ From his description it appears that there are three leaf-beds, varying in thickness from 14 to 24 feet, which are interstratified with volcanic tuff and trap, the whole mass being about 130 feet in thickness. A sheet of basalt 40 feet thick covers the whole ; * See Sig. Gioy. Mienelotti’s works, + Quart. Geol. Journ. 1851, p. 89. 180 PLIOCENE ‘AND MIOCENE FORMATIONS [Cu. XIV and another columnar bed of the same rock 10 feet thick is exposed at the bottom of the cliff. One of the leaf-beds consists of a compressed mass of leaves unaccompanied by any stems, as if they had been blown into a marsh where a species of Hauisetum grew, of which the remains are plentifully imbedded in clay. It is supposed by the Duke of Argyle that this formation was accumu- lated in a shallow lake or marsh in the neighborhood of a volcano, which emitted showers of ashes and streams of lava. The tufaceous envelope of the fossils may have fallen into the lake from the air as volcanic dust, or have been washed down into it as mud from the adjoining land. The deposit is decidedly newer than the chalk, for chalk flints contaming cre- taceous fossils were detected by the Duke in the principal mass of vol- canic ashes or tuff.* The leaves belong to species, and sometimes even to families, no longer indigenous in the British Isles; and “their climatal aspect,” says Pro- fessor E. Forbes, “ is more mid-European than that of the English Eocene Flora. They also resemble some of the Miocene plants of Croatia de- scribed by Unger.” Some of them appear to belong to a coniferous tree, possibly a yew (Zazxus) ; others, still more abundant, to a plane (Platanus), having the same outline and veining well preserved. No accompanying fossil shells have been met with, and there seems therefore the same un- certainty in determining whether these beds are Upper Eocene or Mio- cene, which we experience when we endeavor to fix the age of many con- tinental Brown-Coal formations, those of Croatia not excepted. These interesting discoveries in Mull naturally raise the question, whether the basalt of Antrim in Ireland, and of the celebrated Giant’s Causeway, may not be of the same age. For in Antrim the basalt over- lies the chalk, and the upper mass of it covers everywhere a bed of lignite and charcoal, in which wood, with the fibre well preserved, and evidently dicotyledonous, is preserved.t The general dearth of strata in the British Isles, intermediate in age between the formation of the Eocene and Plio- cene periods, may arise, says Professor Forbes, from the extent of dry land which prevailed in the last interval of time alluded to. If land predomi- nated, the only monuments we are likly ever to find of Miocene date are those of lacustrine and volcanic origin, such as these Ardtun beds in Mull, or the lignites and associated basalts in Antrim. On the flanks of Mont Dor, in Auvergne, I have seen leaf-beds among the ancient volcanic tuffs which I have always supposed to be of Miocene date. Some of the Brown-Coal deposits of Germany are believed to be Miocene; others, as will be seen in the next chapter, are Eocene, Upper or Middle. Older Pliocene and Miocene formations in the United States—Be- tween the Alleghany mountains, formed of older rocks, and the Atlantic, there intervenes, in the United States, a low region occupied principally by beds of marl, clay, and sand, consisting of the cretaceous and tertiary formations, and chiefly of the latter. The general elevation of this plain * Quart. Geol. Journ. 1851, p. 90. + Duke of Argyle, ibid. p. 101. Cz. XIV] IN UNITED STATES, AND IN INDIA. 181 bordering the Atlantic does not exeeed 100 feet, although it is sometimes seyeral hundred feet high. Its width in the middle and southern states is very commonly from 100 to 150 miles. It consists, in the south, as in Georgia, Alabama, and South Carolina, almost exclusively of Eocene de- posits; but in North Carolina, Maryland, Virginia, Delaware, more modern strata predominate, which, after examining them in 1842, I sup- posed to be of the age of the English crag and Faluns of Touraine.* If, chronologically speaking, they can be truly said to be the representatives of these two European formations, they may range in age from the Older Pliocene to the Miocene epoch, according to the classification of European strata adopted in this chapter. The proportion of fossil shells agreeing with recent, out of 147 species collected by me, amounted to about 17 per cent. or one-sixth of the whole ; but as the fossils so assimilated were almost always the same as species now living in the neighboring Atlantic, the number may hereafter be augmented, when the recent: fauna of that ocean is better known. In different localities, also, the proportion of recent species varied con- siderably. On the banks of the James River, in Virginia, about 20 miles below Richmond, in a chff about 30 feet high, I observed yellow and white sands overlying an Eocene marl, just as the yellow sands of the crag lie on the blue London clay in Suffolk and Essex in England. In the Vir- ginian sands, we find a profusion of an Astarte (A. undulata, Conrad), which resembles closely, and may possibly be a variety of, one of the commonest fossils of the Suffolk Crag (A. bipartita); the other shells also, of the genera Watica, Fissurella, Artemis, Lucina, Chama, Pectun- culus, and Pecten, are analogous to shells both of the English crag and French faluns, although the species are almost all distinct. Out of 147 of these American fossils I could only find 13 species common to Europe, and these occur partly in the Suffolk Crag, and partly in the faluns of Fig. 164, Fig. 165. Fulgur canaliculatus. Maryland. Fusus quadricostatus, Say. Maryland. Touraine ; but it is an important characteristic of the American group, that it not only contains many peculiar extinct forms, such as Husus * Proceed. of the Geol. Soc. vol. iv. part 3, 1845, p. 547. 182 PLIOCENE AND MIOCENE FORMATIONS, ETC. [Cs. XIV quadricostatus, Say (see fig. 165), and Venus tridacnoides, abundant im these same formations, but also some shells which, like Yulgur carica ot Say and F. canaliculatus (see fig. 164), Calyptreea costata, Venus merce- naria, Lam., Modiola glandula, Totten, and Pecten magellanicus, Lam., are recent species, yet of forms now confined to the western side of the Atlantic,—a fact implying that some traces of the beginning of the pres- ent geographical distribution of mollusca date back to a period as remote as that of the Miocene strata. Of ten species of zoophytes which I procured on the banks of the James River, one was formerly supposed by Mr. Lonsdale to be identical with a fossil from the faluns of Touraine, but this species (see fig. 166) proves on re-examination to be different, and to Fig. 166, agree generically with a coral now living on the coast of the United States. With respect to climate, Mr. Lonsdale regards these corals as indicating a temperature exceeding that of the Mediterranean, and the shells would lead to sim- ilar conclusions. Those occurring on the James River are in the 37th degree of N. latitude, while the French faluns are in the 47th; yet : a Astrangia lineata, Lonsdale. the forms of the American fossils would scarcely Syn. Anthophyllum lineatum. ee yuan nneae imply so warm a climate as must have prevailed — W!/7amsburs, Virginia in France when the Miocene strata of Touraine originated. Among the remains of fish in these Post-Eocene strata of the United States are several large teeth of the shark family, not distinguishable specifically from fossils of the faluns of Touraine. India. —Sewélik Hills—The freshwater deposits of the sub-Hima- layan or Sewalik Hills, described by Dr. Falconer and Captain Cautley, belong probably to some part of the Miocene period, although it is diffi- cult to decide this question until the accompanying freshwater and land- shells have been more carefully determined and compared with fossils of other tertiary deposits. The strata are certainly newer than the num mulitic rocks of India, and, like the faluns of Touraine, they contain the genera Deinotheri:im and Mastodon, with which are associated no less than seven extine: species of elephants. The presence of a fossil giraffe and hippopotamus, genera now only living in Africa, and of a camel, an inhabitant of extensive plains, implies a former geographical state of things strongly contrasted with what now prevails in the same region. A species of Anoplotherium (A. posterogenium) forms a link between this fauna and that of the Eocene period ; yet, on the whole, the Sewalik mammalia have a more modern aspect than those of the Upper Eocene, so many being referable to existing genera, whereas almost every Eocene genus is extinct. Moreover, the sub-Himalayan fauna exhibits a great development of the Ruminants, an order so feebly represented in the Eocene period. In addition to the camel and giraffe already alluded to, we have here the huge Sivatherium, a ruminant bigger than the rhi- noceros, and provided with a large upper lip, if not a short proboscis, and Cx, XV.] UPPER EOCENE FORMATIONS. 183 having two pair of horns resembling those of antelopes. The number of species of the genus Antelope is also remarkable. In the same fauna appear many carnivorous beasts, often belonging to existing genera, and several species of monkey. Among the reptiles are crocodiles, some Jarger than any now living ; and an enormous tortoise, Zestudo Atlas, the eurved shell of which measured twenty feet across. CHAPTER XV. UPPER EOCENE FORMATIONS. (Lower Miocene of many authors.) Preliminary remarks on classification, and on the line of separation between Eocene and Miocene strata—Whether the Limburg and contemporaneous for- mations should be called Upper Eocene—Limburg strata in Belgium—Strata of same age in North Germany—Mayence basin—Brown Coal of Germany— Upper Eocene of Hempstead Hill, Isle of Wight—Upper Eocene of France— Lacustrine strata of Auvergne—Indusial limestone—Freshwater strata of the Cantal—Its resemblance in some places to white chalk with flints—Proofs of gradual deposition—Upper Eocene of Bourdeaux, Aix-en-Provence, Malta, &c. —Upper Eocene of Nebraska, United States. Preliminary remarks.—In the last chapter it was stated that as yet we know of no marine strata in the British Isles contemporaneous with the faluns of Touraine, or those shelly deposits of the valley of the Loire which I selected as the type of the Miocene period. There have, how- ever, been recently discovered in the Isle of Wight certain fluvio-marine deposits, which many continental geologists would call “ Lower Miocene,” the “faluns” being termed by them “Upper Miocene.” A few prelimi- nary remarks on this difference of nomenclature, bearing as it does on questions involving the first principles of classification, will be necessary before I treat of the Upper Eocene formations. The marine strata, which in the north of France come next in chrono- logical order to the “ faluns,” or which immediately precede them in age, are the sands and sandstones, called the “Grés de Fontainebleau,” or “sables marins supérieurs.” (See General Table, p. 104.) They consti- tute the uppermost beds of the Paris basin, and are overlaid by a fresh- water limestone called “ Calcaire dela Beauce.” The upper marine sands éontain no fossil shells common to the faluns, or extremely few species ; and no shells of living species, or, if so, they are about as scarce as in the Middle or typical Eocene groups. In consequence of this distinctness in the fossils, and for other reasons presently to be mentioned, I excluded these “upper sands” from the Miocene period in former editions of this work, availing myself of the hiatus between the Grés de Fontainebleau and the faluns to draw a line of separation between Eocene and Miocene. 184 REMARKS ON CLASSIFICATION. [Cu. XV Tn support of this classification I pointed out the fact that the “ upper marine sands,” or Grés de Fontainebleau of the Parisian series, with their characteristic shells, extend southwards from the French metropolis, as far as Etampes, which is within seventy miles of Pontlevoy, near Blois, aud not more than 100 miles from Savigné, near Tours, two localities where the falunian shells are very abundant. So remarkable a difference between the species of the valley of the Loire and those of the valley of the Seine cannot be the result of geographical distribution at one and the same former era, but must evidently have depended on a differ- ence in the age of the deposits. It marks the influence of Time, and not of Space. Another reason which induced me to class the Grés de Fontainebleau and strata of the same age with the older series rather than with the newer, was the decidedly Eocene aspect of the testaceous fauna, and the fact that a certain proportion of the shells of the “upper sands” are of species common to the underlying Parisian strata. A different arrangement, however, was adopted by MM. Dufrénoy and E. de Beaumont, in their coloring of the Government Map of France, for they comprehended in their Miocene group, not only the faluns of Tou- raine, but also the freshwater “ calcaire de la Beauce,” and the marine sands and sandstone (Grés de Fontainebleau), 7. e. all the tertiary de- posits which lie above the gypseous series of Montmartre, a formation well known as rich in extinct mammalia, first brought to light by the genius of Cuvier. M. D’Archiac, in 1839, followed the same mode of classification, dividing what he termed “ Lower” from his “ Middle ter- tiary” in the same way. M. Deshayes, in his work on the Fossil Shells of the Environs of Paris (1824-1837), had given twenty-nine species as belonging to the upper marine strata, nearly all of which he distin- guished specifically from shells of the Calcaire Grossier, although he regarded them as characteristic of the same fauna. The railway cut- tings near Etampes, in 1849, enabled M. Hébert to raise the number to ninety, and he first pointed out that most of them agreed specifically with shells of Kleyn Spawen, near Maestricht, in Belgium, and with those of Rupelmonde and other places near Antwerp. These Belgian fossils had been described by MM. Nyst, De Koninck, and Bosquet, and their geological position had been accurately ascertained by M. Dumont, and placed by him above the Brussels tertiary beds, which are the un- doubted representatives of the Calcaire Grossier of Paris, a typical Eocene group. M. de Koninck, about the same time, remarked that the Kleyn Spawen, or “ Limburg” fossils, were in part identical with those of the Mayence tertiary basin, a group which in my first editions I had assigned to the Miocene period. M. Beyrich more recently (1850) has described a formation of the same age as that of Kleyn Spawen, occurring within seven miles of the gates of Berlin, near the village of Hermsdorf; and has shown that about a third of the species agreed with known Belgian shells of the age of the Grés de Fontainebleau, while about a fifth are English and French Middle Eocene species. Cu. XV.] UPPER EOCENE FORMATIONS. 185 In 1851, I examined with care the Belgian formations at Rupelmonde and Boom, near Antwerp, and in the Limburg, near Maestricht, and was able, with the assistance of M. Bosquet, to give a table of no less than 201 species of shells of the era under consideration. Of these more than a third proved to be identical with English Eocene testacea, even when I restricted the term Eocene to its most limited sense, extending it no farther upwards than the Middle Eocene or nummulitic formations.* For this reason I called the Limburg or Kleyn Spawen beds Upper Eocene, giving as my reason “ that they resembled the older formations in their fossils as much as some of the different divisions of the Eocene series in France and England resemble each other ; as much, for exam- iple, as the Barton Clay in Hampshire agrees with the London Clay proper, or the Calcaire Grossier with the Soissonnais sands in France.” Subsequently, in the winter of 1852, Professor Edward Forbes exam- ined near Yarmouth, in the Isle of Wight, a deposit occupying a very limited area, but about 170 feet in thickness, which he first determined to be of the same age as the Limburg beds. They were found to be in conformable position with the other tertiary strata previously known in that island, and to contain abundantly some of the most characteristic Kleyn Spawen fossils. He named this deposit “the Hempstead series,” and classed it as Upper Eocene, for reasons similar to those which had induced me so to name the Limburg beds of Belgium. They cannot in fact be separated from the subjacent Eocene strata without drawing a line of demarcation confessedly arbitrary, and which would leave a great many of the same species of fossils above and bélow it. So complete, indeed, is the passage from the Bembridge series (an equivalent of the gypsum of Montmartre, and therefore an acknowledged Eocene forma- tion) into the Hempstead beds, that Professor Forbes places both groups together in his Upper Eocene division, drawing the line between Upper and Middle Eocene at the base of the Bembridge beds. In opposition to this view two recent authorities, who in the course of the present year (1853) have written on the tertiary formations of Ger- many, M. Beyrich, before cited,t and Dr. Sandberger,{ contend that all strata, parallel in age with the Limburg, should be termed Lower Mio- cene. M. Beyrich affirms that if the strata of the Bolderberg in Bel- gium, and numerous deposits of contemporaneous date of Northern Germany already enumerated (p. 178), be of the age of the “faluns,” then it can be shown that these same beds have so many fossils in common with the Limburg strata, that the latter may fairly be regarded as Miocene, or as an older deposit of the same great.period ; and he goes on to say that, unless we are prepared to allow the Eocene division to absorb all the overlying tertiary formations, we must begin a new series from the base of the Limburg upwards, calling the latter Lower * Quart. Geol. Journ. 1852, vol. viii. p. 322. * ¢ Die Conchylien des Norddeutsch. Tertiirgeb.: Berlin, 1853. ¢ Uber das Mainzer Tertiirbeckens, &e.: Wiesbaden, 1853. 186 SEPARATION OF EOCENE AND MIOCENE STRATA. [Cu XV. Miocene. Dr. Sandberger divides the strata of the Mayence basin into two sections, an older and a newer, the former confessedly the equiva- lent of the Limburg (or Hempstead) beds, while in the upper he finds some fossil remains, which appear to him to have a more modern char- acter. But when we separate from this higher division the sands of Eppelsheim, containing bones of Deinotherium and Mastodon longirostris, which are most probably of falunian age, the rest of his upper series may be as old as the Limburg beds, though, for want of good sections, there is much obscurity in regard to the grouping of the beds. Dr. Sandberger, however, gives a list of twelve shells, besides some teeth of fish and other fossils, which are common to the Mayence basin and the Hesse-Cassel sands. Now the latter were classed as Subapennine or Pliocene by Philippi, and, although we have as yet no sufficient data or determining their true age, appear clearly to belong to a more mod- ern fauna than that of the Mayence basin. If such a relationship could be established between the two as to indicate a passage from the Hesse- Cassel fauna to that of the Mayénce beds, this fact would doubtless go some way towards bearing out the views of the author. The reader has probably by this time begun to perceive that one cause of embarrassment, experienced in the classification of these ter- tiary formations, arises from the discovery of several missing links in the chain of historical records. I may remind him that for more than twenty years I have advocated in the Principles of Geology the doctrine that there has been a continual coming in of new species, and dying out of old ones, and a gradual change in the physical geography and cli- mate of the earth, and not such a reiteration of sudden revolutions in the animate and inanimate worlds, as was once insisted upon by many Eng- lish geologists of note, and is still maintained by not a few of the most distinguished continental writers. When, therefore, I proposed in 1833 the term Miocene for the faluns of Touraine, the fossil shells of which, according to the determination of M. Deshayes, contained an admixture of about seventeen in the hundred of recent species, I foretold that from time to time new sets of strata would come to light, and require to be intercalated between those already described, and in that case that the fossils of newly-found beds would “ deviate from the normal types first selected, and approximate more and more to the types of the ante- cedent or subsequent epochs.” According to this view, it was obvious from the first that the oldest Miocene records, whenever they were detected, would not be easily distinguishable from the youngest members of the Eocene series, especially in the proportion of the living to the extinct species of fossil shells. The importance, indeed, of the latter test must diminish rapidly the more we recede from the Pliocene and approach the Miocene, and still more the Eocene for- mations, although it is never without its value, and often furnishes the only common standard of comparison between strata of very distant countries. I make these allusions to show that Iam by no means unprepared Cn. XV.] EOCENE AND MIOCENE STRATA. 187 for the discovery of gradations from Miocene to Eocene, and for the probable necessity of including hereafter in the Miocene series some fossiliferous groups which may diverge in their characters from the standard first set up, or from the type of the faluns of Touraine. But I have seen, as yet, no sufficient evidence that such a passage, as is here spoken of, has been made out. The limits of the Eocene series have been extended, without as yet filling up the gap between that series and the faluns of Touraine. I am desirous at the same time to explain, that the important point now at issue is not simply one of nomenclature. The difficulty is the same, whether we use the terms Lower and Middle Tertiary, or Eocene and Miocene. To one or other of the periods so named we must refer the Limburg and Hempstead beds, and the sands of the Forest of Fontainebleau. Can we, without doing violence to paleonto- logical principles, refer all these to the same period as the faluns of Touraine? If so, it would be immaterial whether we called them Middle Tertiary, Miocene, or “ Falunian,” or by any other general name. The question is, whether, in the present state of our information, the mass of characteristic fossils of the groups alluded to resemble more nearly the Eocene or the Falunian. I adhere at present to the nomen- clature formerly adopted by me for strata described in this chapter, calling them Upper Eocene—not because of the small number of living species of shells found in them, although this is certainly one point of agreement between them and the “nummulitic” Eocene beds, but be- cause of the aspect of the whole fauna, which seems to me to be Eocene rather than Falunian. Among other illustrations of this affinity, I may ~ refer the reader to the numerous and excellent figures of species of the genus Voluta given by M. Beyrich from the Limburg beds of North Germany—forms strikingly characteristic of the Barton clay in Hamp- shire, a regular member of the Middle Eocene group. The faluns are devoid of such forms. Until, therefore, the time arrives when the break between the Limburg beds and the faluns has disappeared more com- pletely, it appears to me safer to include the Limburg and all contem- poraneous formations in the Hocene. ; At the same time I have drawn the line between Middle and Upper Eocene, as in former editions, excluding from the latter the Bembridge beds of the Isle of Wight, or the gypseous series of Montmartre. A preference is given to this last method, simply for convenience sake, in order that the Upper Eocene of this work may coincide exactly with the strata classed by so many distinguished geologists as Lower Miocene. I am bound, however, to state, that the parting line between the Bem- bridge and Hempstead series, in the Isle of Wight, has been shown by Professor Forbes to be an arbitrary one—a purely conventional line, if any thing, less marked than the line separating the Bembridge series from the underlying St. Helen’s group. (See Table, p. 209.) If re- tained as more useful, it is, as before hinted, for the sake of confor- mity with a system of classification adopted by many able geologists, who selected it before the uninterrupted continuity of the Eocene series 188 LIMBURG STRATA IN BELGIUM. [Ca XV" from its nummulitic or central portions to its Upper or Limburg beds was clearly made out. LIMBURG STRATA IN BELGIUM. (Rupelian and Tongrian Systems of Dumont.) The best type which we as yet possess of the Upper Eocene, as defined in the foregoing observations, consists of the beds formerly known to col- lectors as those of Kleyn Spawen. These can be best studied in the environs of the village so named, which is situated about seven miles west of Maestricht, and in the old province of Limburg in Belgium. In that region, about 200 species of testacea, marine and freshwater, have been obtained, with many foraminifera and remains of fish. The following table will show the position of the Limburg beds. MI0cENE. A. Bolderberg beds, see p. 178, seen near Hasselt. Upper Eocene. B. 1. Nucula Loam of Kleyn Spawen, same ) Upper Limburg beds.—Rupelian age as clay of Rupelmonde and Boom. of Dumont. B. 2. Fluvio-marine beds of Bergh, Lethen, ) Middle Limburg beds. — Upper and other places near Kleyn Spawen. Tongrian of Dumont. B. 3. Green sand of Bergh, Neerepen, c&e., ) Lower Limburg Beds. — Lower near Kleyn Spawen: Marine. Tongrian of Dumont. Mipp1e Eocene. C. Lacken and Brussels beds, with num- mulites, &c.: Louvain and Brussels. The uppermost of the three subdivisions (B. 1) into which the Limburg series is separated in the abova table, contains at Kleyn Spawen many of the same fossils as the clay 0! Rupelmonde and Boom, ten miles south of Antwerp, and sixty miles N. W. of Kleyn Spawen. About forty species of shells have been collected from the tile-clay worked on the banks of the Scheldt at the villages above mentioned. At Rupelmonde, this clay attains a thickness of about 100 feet, and much resembles in mineral character the “London Clay,” containing like it septaria or concretions of argillactous limestone traversed by cracks in the interior. The shells have been described by MM. Nyst and De Koninck. Among them Leda (or Nucula) Deshayesiana (see fig. 167) is by far the most abun- Fig. 167. Leda Deshayesiana. Nyst. Syn. Nucula Deshayestana. oe Cx. XV.] STRATA IN NORTH GERMANY. 189 dant; a fossil unknown as yet in the English tertiary strata, but when young much resembling Leda amygdaloides of the London clay proper (see fig. 227, p. 218). Among other characteristic shells are Pecten Hoeninghausi, and a species of Cassidaria, and several of the genus Pleurotoma. Not a few of these testacea agree with English Eocene species, such as Actwon simulatus, Sow., Cancellaria evulsa, Brander, Corbula pisum (fig. 170, p. 193), and Wawtilus ziczac. They are accom- panied by many teeth of sharks, as Zamna contortidens, Ag., Oxyrhina aiphodon, Ag., Carcharodon heterodon (see fig. 211), Ag., and other fish, some of them common to the Middle Eocene strata. The same deposit, B. 1, is very imperfectly seen at Kleyn Spawen, where the lower divisions _B. 2 and B. 3 are much better developed. 3B. 2 consists of several alter- nations of sands and marls, in which a greater or less intermixture of fluviatile and marine shells occurs, implying the occasional entrance of a river near the spot, and possibly oscillations in the level of the bottom of the sea. Among the shells are found Cyrena semistriata (fig. 171, p. 193), Cerithium plicatum, Lam. (fig. 172, p. 193), Rissoa Chastelit, Bosq. (fig. 174), and Corbula pisum (fig. 170), four shells all common to the Hempstead beds in the Isle of Wight, to be mentioned in the sequel. With the above, Lucina Thierensii, and other marine forms of the genera Venus, Limopsis, Trochus, &c., are met with. In B. 3, or the Lower Limburg, more than 100 marine shells have been collected, among which the Ostrea ventilabrum is very conspicuous. Spe- cies common to the underlying Brussels sands, or the Middle Hocene, are numerous, constituting a third of the whole; but most of these are feebly represented in comparison with the more peculiar and characteristic shells, such as Ostrea ventilabrum, Mytilus Nystii, Voluta saturalis, &c. In none of the Belgian Upper Eocene strata, could I find any nummu- lites; and M. D’Archiae had previously observed that these foraminifera characterize his “ Lower Tertiary Series,” as contrasted with the Middle, anc would therefore serve as a good test of age between Eocene and Mio- cene, if the line of demarcation be drawn according to his method, or equally so between Upper and Middle Eocene, according to the plan adopted in this work. The same naturalist informs us that one nummu- lite only has ever yet been seen to penetrate upwards into the middle tertiary, viz., Wummulites intermedia, an Eocene species. It has been found in the hill of the Superga near Turin,* in beds usually classed as Miocene, but probably somewhat older than the falunian type. Hermsdorf, near Berlin —Professor Beyrich has described a mass of clay, used for making tiles within seven miles of the gates of Berlin, near the village of Hermsdorf, rising up from beneath the sands with which that country is chiefly overspread. This clay is more than forty feet thick, of a dark bluish-gray color, and, like that of Rupelmonde, contains septaria. Among other shells, the Leda Deshayestana before mentioned (fig. 167) abounds, together with many species of Plewrotoma, Voluta, &c., * Archiac, Monogr. pp. 79, 100. 190 - MAYENCE BASIN. [Cu. XV: a certain proportion of the fossils being identical in species with Limburg and Mayence shells. M. Beyrich enumerates several other localities in North Germany, and particularly one at Magdeburg, and several on the Lower Elbe, where beds of the same age appear. - Mayence basin—lI have already alluded to the elaborate description published by Dr. F. Sandberger of the Mayence tertiary area, which oc- cupies a tract from five to twelve miles in breadth, extending for a great distance along the left bank of the Rhine from Mayence to the neighbor- hood of Manheim, and which is also found to the east, north, and south- west of Frankfort. M. De Koninck, of Liége, first pointed out to me that the purely marine portion of the deposit (the Lower group of Dr. Sand- berger) contained many species of shells common to the Limburg beds near Kleyn Spawen, and to the clay of Rupelmonde, near Antwerp. Among these he mentioned Cassidaria depressa, Tritenium argutum, Brander (T. flandricum, De Koninck), Tornatella simulata, Rostellaria Sowerbyi, Leda Deshayesiana (fig. 167, p. 188), Corbula pisum (fig. 170), and Pectunculus terebratularis. The marine beds are in some places covered with brackish-water marls containing Cyrene in great numbers, among which Cyrena semis- triata occurs, with Cerithium plicatum, Corbulomya triangula, Mytilus Fanjasii, and other Limburg and Hempstead shells. Perna Soldani, a shell of the upper Eocene or Mérignac beds of the Bourdeaux basin, but also a Vienna basin shell, is characteristic both of the marine and brackish series. Two species of Anthracotherium, A. magnum, Cuv., and A. al- saticum, are met with in the same deposits. The upper portion of this Mayence series has at its base a limestone full of Certthia and land-shells ; among which Cerithiwm plicatum before mentioned, and another Limburg shell, Venus incrassata, Sow., a fossil common to the Headon or Middle Eocene of England, are met with ; alse Neritina concava (fig. 194), a Middle Eocene shell, and Rhinoceros in- céstvus,.the oldest form of that genus, and called by Kaup Acerotherium. Next above is a limestone, in which Littorinella or Paludina inflata is a very common fogsil, with others of the same genus. One of these, very nearly resembling the recent Littorinella ulva, is found through- out this basin. These shells are like grains of rice in size, and are often in such quantity as to form entire beds of marl and limestone, in stratified masses from fifteen to thirty feet in thickness, just as in the Baltic modern accumulations several feet thick of the Zittorinella ulva are spread far and wide over 7iuainas the bottom of the sea. In the same beds, several species of Dreissena abound, a form common to the Headon or Middle Eocene beds of the Isle of Wight, as well as to the existing seas. On the whole, lam not satisfied that this fauna diverges from the Limburg type towards that of the faluns as much as Dr. Sandberger believes. Among the Mammalia, we find Hippotherium gracile, Acerotherium (or Rhinoceros) incisivum, Paleomeryx, Chalicomys, &e. Lastly, the Eppelsheim sand overlies the whole, containing Deinotherium giganteum, and some other true Miocene Fig. 168, Cx. XV.] BROWN COAL OF GERMANY. 191 quadrupeds. Several mammalia, proper to the Upper Eocene series, are also said to be associated ; but there being no good section at Eppelsheim, the true succession of the beds from which the bones were dug out cannot be seen, and we have yet to learn whether some remains of an older series may not have been confounded with those of a newer one. Brown coal of Germany.—In a recent essay on the Brown Coal de- posits of Germany, Baron Von Buch has expressed a decided opinion that they all belong to one epoch, being of subsequent date to the great nummulitic period, and older than the Phocene formations. He has therefore called the whole Miocene. Unfortunately, these formations rarely contain any internal evidence of their age, except what may be derived from plants, constituting in every case but a fraction of an ancient Flora, and consisting of mere leaves, without flowers or fruits. It is often therefore impossible ‘to form more than a conjecture as to the precise place in the chronological series which should be assigned to each layer of lignite or each leaf-bed. Nevertheless, enough is known to show that some of the Brown Coals found in isolated patches be- long to the Upper Eocene, others to the Miocene, and some perhaps to the Pliocene eras. They seem to have been formed at a period when the European area had already a somewhat continental character, so that few contemporaneous marine or even fluvio marine beds were in progress there. The brown coal of Brandenburg, on the borders of the Baltic, under- lies the Hermsdorf tile-clay already spoken of, and therefore belongs to a period at least as old as the Upper Eocene. The brown coal of Radoboj, on the confines of Styria, is covered, says Von Buch, by beds containing the marine shells of the Vienna basin, which, as before remarked, are chiefly of the Falunian or Miocene type. This lignite, therefore, may be of Miocene or Upper Eocene date, a point to be deter- mined by the botanical characters of the plants. In this, and most of the principal brown coal formations, several species of fan-palm or Flabellaria abound. This genus also appears in the Middle Eocene or Bem- bridge beds in the Isle of Wight, and in the gypseous series of Montmartre; but it is still more largely represented in the Upper Eo- cene series, accompanied by palms of the genus Phenicites. Various cones, and the leaves and wood of coniferous trees, are also met with at Radoboj. Species also of Comptonia and Myrica, with various trees, Daphnogene cinnamomifolia, such as the plane or Platanus, are recog- teste poe nized by their leaves, as also several of the Laurel tribe, especially one, called Daphnogene cinnamomifolia (fig. 169) by Unger, who, together 192 UPPER EOCENE STRATA OF ENGLAND. [Ca. XV. with Géppert, has investigated the botany of these formations. It will be seen that in the leaf of this Daphnogene two veins branch off on each side from the mid-rib, and run up without interruption to the point. On the Lower Rhine, whether in the Mayence basin or in the Sieben- gebirge, and in the neighborhood of Bonn and Cologne, there seem to be Brown Coals of more than one age. Von Buch tells us that the only fossil found in the Brown Coal near Cologne, one often met with there in the excavation of a tunnel, is the peculiar fruit, so like a cocoa- nut, called Nipadites or Burtonia Fanjasii (see fig. 220). Now this fossil abounds in the Lower Eocene or Sheppy clay near London, also in the Middle Eocene at Brussels; and I found it still higher in the same nummulitic series at Cassel, in French Flanders. This fact taken alone would rather lead us to refer the Cologne lignite to the Eocene period. Some of the lignites of the Siebengebirge near Bonn associated with volcanic rocks, and those of Hesse Cassel which accompany basaltic out- pourings, are certainly of much later date. UPPER EOCENE STRATA OF ENGLAND. Hempstead beds.—Isle of Wight—Until very lately it was supposed by English geologists that the newest tertiary strata of the Isle of Wight corresponded in age with the gypseous series of Montmartre near Paris ; and this idea was confirmed by the fact that the same species of Palco- therium, Anoplotherium, and other extinct mammalia so characteristic of the Parisian series, were also found at Binstead, near Ryde, in the north- ern district of the island, forming part of the fluvio-marine series. We are indebted to Prof. E. Forbes for having discovered in the autumn of 1852 that there exist three formations, the true position of which had been overlooked, all of them newer than the beds of Headon Hill, in Alum Bay, which last were formerly believed to be the uppermost part of the Isle of Wight tertiary series.* The three overlying formations to which I allude are as follows :— Ist, certain shales and sandstones called the St. Helen’s beds (see Table, p. 104, e¢ seg.) rest immediately upon the Headon series; 2dly, the St. Helen’s series is succeeded by the Bembridge beds before men- tioned, the equivalent of the Montmartre gypsum; and 3dly, above the whole is found the Upper Eocene or Hempstead series. This newer deposit, which is 170 feet thick, has been so called from Hempstead Hill, near Yarmouth, in the Isle of Wight.t The following is the suc- cession of strata there discovered, the details of which are important for reasons explained in the preliminary remarks of this chapter (p. 187) :-— * E. Forbes, Geol. Quart. Journ. 1853. ¢ This hill must not be confounded with Hampstead Hill, near London, where the Lower Eocene or London Clay is capped by Middle Eocene sands. Cz. XV.] UPPER EOCENE, ISLE OF WIGHT. 193 SUBDIVISIONS OF THE HEMPSTEAD SERIES. 1. The uppermost or Corbula beds, consisting of marine sands and clays, contain Corbula pisum, fig. 170, a species common to the Middle Eocene clay of Barton; Cyrena semistriata, fig. 171, which is also a Middle Eocene fossil; | several Cerithia, and other shells peculiar to this series, Fig. 170. Fig. 171. Corbula pisum. Hempstead Beds, Cyrena semistriata, Isle of Wight. Hempstead Beds. 2. Next below are freshwater and estuary marls and carbonaceous clays, in the brackish-water portion of which are found abundantly Cerithium plicatum, Lam., fig. 172, C. elegans, fig. 173, and C. tricinctum ; also Rissoa Chastelii, fig. 174, a very common Limburg shell, and which occurs in each of the four subdivisions of the Hempstead series down to its base, where it passes into the Bembridge beds. In the freshwater portion of the same beds Paludina Fig. 172. Fig. 173. Fig. 174. Fig. 175. Cerithium plicatum, Cerithium elegans, Rissoa Chastelii, Nyst, Paludina lenta. Lam, Hempstead, Hempstead. eee Isle Hempstead Beds, of Wight. lenta, fig. 175, occurs a shell identified by some conchologists with a species now living, P. unicolor ; also several species of Lymneus, Planorbis, and Unio. 3, The next series, or middle freshwater and estuary marls, are distinguished by the presence of Melania fasciata, Paludina lenta, and clays with Cypris ; the lowest bed contains Cyrena semistriata, fig.171, mingled with Cerithia and a Panopea. 4, The lower freshwater and estyary marls contain Melania costata, Sow., Me- lanopsis, &c. The bottom bed is carbonaceous, and called the “ Black band,” in which Kissoa Chastelii, fig. 173, before alluded to, is common, This bed contains a mixture of Hempstead shells with those of the underlying Middle Eocene or Bembridge series. The seed-vessels of Chara medicaginula, Brong., and (. helecteras are characteristic of the Hempstead beds generally. The mammalia, among which is a species of Hyotherium, differ, so far as they are known, from those of the Bembridge beds immediately underlying. ; 13 194 UPPER EOCENE STRATA OF FRANCE. [Cz. XV Between the Hempstead beds above described and those next below them, there is no break, as before stated, p. 187. The freshwater, brackish, and marine limestones and marls of the underlying or Bembridge group are in conformable stratification, and contain Cyrena semistriata, fig. 171, Melania muricata, Palu- dina lenta, fig. 175, and several other shells belonging to the Hempstead beds. Prof. Forbes therefore classes both of them in the same Upper Eocene division. I have called the Bembridge beds Middle Eocene, for convenience sake, as already explained (pp. 1838, 187.) UPPER EOCENE STRATA OF FRANCE, (Lower Miocene of many French authors.) The Grés de Fontainebleau, or sandstone of the Forest of Fontainebleau, has been frequently alluded to in the preceding pages, as corresponding in age to the Limburg or Hempstead beds. It is associated in the sub- urbs of Paris with a set of strata, very varied in their composition, and containing in their lower portion a green clay with abundance of small oysters ( Ostrea cyathula, Lam.) which are spread over a wide area. The marine sands and sandstone which overlie this clay include Cytherea én- crassata and many other Limburg fossils, the finest collections of which have been made at Etampes, south of Paris, where they occur in loose sand. The Grés de Fontainebleau is sometimes called the “ Upper marine sands” to distinguish it from the “ Middle sands” or Grés de Beauchamp, a Middle Eocene group. Calcaire lacustre supérieur—Above the Grés de Fontainebleau is seen the upper freshwater limestone and marl, sometimes called Caleaire de la Beauce, which with its accompanying marls and siliceous beds seem to have been formed in marshes and shallow lakes, such as frequently over- spread the newest parts of great deltas. Beds of flint, continuous or in nodules, accumulated in these lakes, and Chare, aquatic plants, already alluded to, left their stems and seed-vessels imbedded both in the marl and flint, together with freshwater and land-shells. Some of the siliceous rocks of this formation are used extensively for millstones. The flat sum- mits or platforms of the hills round Paris—large areas in the forest of Fontainebleau, and the Plateau de la Beauce, between the Seine and the Loire, are chiefly composed of these upper freshwater strata. When they reach the valley of the Loire, they occasionally underlie and form the boundary of the marine Miocene faluns, fragments of the older freshwater limestone having been broken off and rolled on the shores and in the bed of the Miocene sea, as at Pontlevoy, on the Cher, where the perforating marine shells of the Miocene period still remain in hollows drilled in the blocks of Eocene limestone. Central France——Lacustrine strata, belonging, for the most part, to the same Upper Eocene series, are again met with in Auvergne, Cantal, -and Velay, the sites of which may be seen in the annexed map. They -appear to be the monuments of ancient lakes, which, like some of those ‘now existing in Switzerland, once occupied the depressions in a mountain- ous region, and haye been each fed by one or more rivers and torrents. Cu. XV.] UPPER EOCENE OF CENTRAL FRANCE. 195 Fig. 176 PARTSSQQBASIN Sancerre SN Yi Freshwater iS Nevers Vevers: q7 SE PS ee ne een Montlucon ° oe ° kes 146 196 SUCCESSION OF CHANGES IN AUVERGNE. [Cz. XV The country where they occur is almost entirely composed of granite and different varieties of granitic schist, with here and there a few patches of secondary strata, much dislocated, and which have probably suffered great denudation. There are also some vast piles of volcanic matter (see the map), the greater part of which is newer than the fresh- water strata, and is sometimes seen to rest upon them, while a small part has evidently been of contemporaneous origin. Of these igneous rocks T shall treat more particularly in another part of this work. Before entering upon any details, I may observe, that the study f these regions possesses a peculiar interest, very distinct in kind from that derivable from the investigation either of the Parisian or English ter- tiary areas. For we are presented in Auvergne with the evidence of a series of events of astonishing magnitude and grandeur, by which the original form and features of the country have been greatly changed, yet never so far obliterated but that they may still, in part at least, be restored in imagination. Great lakes have disappeared,—lofty moun- tains have been formed, by the reiterated emission of lava, preceded and followed by showers of sand and scorize,—deep valleys have been sub- sequently furrowed out through masses of lacustrine and volcanic origin, —at a still later date, new cones have been thrown up in these valleys,— new lakes have been formed by the damming up of rivers,—and more than one creation of quadrupeds, birds, and plants, Eocene, Miocene, and Pliocene, have followed in succession ; yet the region has preserved from first to last its geographical identity ; and we can still recall to our thoughts its external condition and physical structure before these wonderful vicissitudes began, or while a part only of the whole had been completed. There was first a period when the spacious lakes, of which we still may trace the boundaries, lay at the foot of mountains of moderate elevation, unbroken by the bold peaks and precipices of Mont Dor, and unadorned by the picturesque outline of the Puy de Dome, or of the volcanic cones and craters now covering the granitic platform. During this earlier scene of repose deltas were slowly formed ; beds of ' marl and sand, several hundred feet thick, deposited ; siliceous and c¢al- careous rocks precipitated from the waters of mineral springs ; shells and insects imbedded, together with the remains of the crocodile and tor- toise, the egos and bones of water birds, and the skeletons of quadru- peds, some of them belonging to the same genera as those entombed in the Eocene gypsum of Paris. To this tranquil condition of the surface succeeded the era of volcanic eruptions, when the lakes were drained, .and when the fertility of the mountainous district was probably enhanced by the igneous matter ejected from below, and poured down upon the more sterile granite. During these eruptions, which appear to have taken place after the disappearance of the upper Eocene fauna, and partly in the Miocene epoch, the mastodon, rhinoceros, elephant, tapir, hippo- potamus, together with the ox, various kinds of deer, the bear, hyzena, and many beasts of prey, ranged the forest, or pastured on the plain, and were occasionally overtaken by a fall of burning cinders, or buried in Cx. XV.] LACUSTRINE STRATA—AUVERGNE. 197 flows of mud, such as accompany volcanic eruptions. Lastly, these quad- rupeds became extinct, and gave place to Pliocene mammalia (see chap. xxxii.), and these in their turn, to species now existing. There are no signs, during the whole time required for this series of events, of the sea having intervened, nor of any denudation which may not have been ac- complished by currents in the different lakes, or by rivers and floods ac- companying repeated earthquakes, during which the levels of the district have in some places been materially modified, and perhaps the whole up- raised relatively to the surrounding parts of France. Auvergne—The most northern of the freshwater groups is situated in the yalley-plain of the Allier, which lies within the department of the Puy de Dome, being the tract which went formerly by the name of the Li- magne d’Auvergne. It is inclosed by two parallel mountain ranges— that of the Foréz, which divides the waters of the Loire and Allier, on the east; and that of the Monts Domes, which separates the Allier from the Sioule, on the west.* The average breadth of this tract is about 20 miles ; and it is for the most part composed of, nearly horizontal strata of sand, sandstone, calcareous marl, clay, and limestone, none of which ob- serve a fixed and invariable order of superposition. The ancient borders of the lake, wherein the freshwater strata were accumulated, may gen- erally be traced with precision, the granite and other ancient rocks rising up boldly from the level country. The actual junction, however, of the lacustrine and granitic beds is rarely seen, as a small valley usually in- tervenes between them. The freshwater strata may sometimes be seen to retain their horizontality within a very slight distance of the border- rocks, while in some places they are inclined, and in few instances vertical. The principal divisions into which the lacustrine series may be separated are the following ;—Ist, Sandstone, grit, and conglomerate, including red marl and red sandstone. 2dly, Green and white foliated marls. 3dly, Limestone or travertin, often oolitic. 4thly, Gypseous marls. 1. a. Sandstone and conglomerate—Strata of sand and gravel, some- times bound together into a solid rock, are found in great abundance around the confines of the lacustrine basin, containing, in different places, pebbles of all the ancient rocks of the adjoining elevated country ; namely, granite, gneiss, mica-schist, clay-slate, porphyry, and others, but without any intermixture of basaltic or other tertiary volcanic rocks. These strata do not form one continuous band around the margin of the basin, being rather disposed like the independent deltas which grow at the mouths of torrents along the borders of existing lakes. At Chamalieres, near Clermont, we have an example of one of these deltas, or littoral deposits, of local extent, where the pebbly beds slope away from the granite, as if they had formed a talus beneath the waters of the lake near the steep shore. A section of about 50 feet in vertical height has been laid open by a torrent, and the pebbles are seen to con- sist throughout of rounded and angular fragments of granite, quartz, * Scrope, Geology of Central France, p. 15. 198 UPPER EOCENE PERIOD. [Cu. XV. primary slate, and red sandstone. Partial layers of lignite and pieces of wood are found in these beds. At some localities on the margin of the basin quartzose grits are found; and, where these rest on granite, they are sometimes formed of separate crystals of quartz, mica, and felspar, derived from the disintegrated granite, the crystals having been subsequently bound together by a siliceous ce- ment. In these cases the granite seems regenerated in a new and more solid form; and so gradual a passage takes place between the rock of crystalline and that of mechanical origin, that we can scarcely distinguish where one ends and the other begins. In the hills called the Puy de Jussat and La Roche, we have the advan- tage of seeing a section continuously exposed for about 700 feet in thick- ness. At the bottom are foliated marls, white and green, about 400 feet thick; and above, resting on the marls, are the quartzose grits, cemented by calcareous matter, which is sometimes so abundant as to form imbed- ded nodules. These sometimes constitute spheroidal concretions 6 feet in diameter, and pass into beds of solid limestone, resembling the Italian travertins, or the deposits ‘of mineral springs. 1. 6. Red marl and sandstone—But the most remarkable of the arenaceous groups is one of red sandstone and red marl, which are iden- tical in all their mineral characters with the secondary Vew Red sand- stone and marl of England. In these secondary rocks the red ground is sometimes variegated with light greenish spots, and the same may be seen in the tertiary formation of freshwater origin at Coudes, on the Al- lier. The marls are sometimes of a purplish-red color, as at Champheix, and are accompanied by a reddish limestone, like the well-known “ corn- stone,” which is associated with the Old Red sandstone of English geol- ogists. The red sandstone and marl of Auvergne have evidently been derived from the degradation of gneiss and mica-schist, which are seen in situ on the adjoining hills, decomposing into a soil very similar to the tertiary red sand and marl. We also find pebbles of gneiss, mica-schist, and quartz in the coarser sandstones of this group, clearly pointing to the parent rocks from which the sand and marl are derived. The red beds, although destitute themselves of organic remains, pass upwards into strata containing tertiary fossils, and are certainly an integral part of the lacustrine formation. From this example the student will learn how small is the value of mineral character alone, asa test of the relative age of rocks. 2. Green and white foliated marls—The same primary rocks of Au- vergne, which, by the partial degradation of their harder parts, gave rise to the quartzose grits and conglomerates before mentioned, would, by the reduction of the same materials into powder, and by the decomposition of their felspar, mica, and hornblende, produce aluminous clay, and, if a sufficient quantity of carbonate of lime was present, calcareous marl. This fine sediment would naturally be carried out to a greater distance from the shore, as are the various finer marls now deposited in Lake Superior. And as, in the American lake, shingle and sand are annually Cu. XV.) LACUSTRINE STRATA—AUVERGNE. 198 amassed near the northern shores, so in Auvergne the grits and con- glomerates before mentioned were evidently formed near the borders. The entire thickness of these marls is unknown; but it certainly ex- ceeds, in some places, 700 feet. They are, for the most part, either light- green or white, and usually calcareous. They are thinly foliated—a character which frequently arises from the innumerable thin shells, or carapace-valves, of that small animal called. Cypris. This animal is pro- vided with two small valves, not unlike those of a bivalve shell, and moults its integuments periodically, which the conchiferous mollusks do not. This circumstance may partly explain the countless myriads of the shells of Cypris which were shed in the ancient lakes of Auvergne, so as to give rise to divisions in the marl as thin as paper, and that, too, in stratified masses several hundred feet thick. A more convincing proof of the tranquillity and clearness of the waters, and of the slow and gradual process by which the lake was filled up with fine mud, cannot be desired. But we may easily suppose that, while this fine sediment was thrown down in the deep and central parts of the basin, gravel, sand, and rocky fragments were hurried into the lake, and deposited near the shore, form- ing the group described in the preceding section. Not far from Clermont, the green marls, containing the Cypris in abundance, approach to within a few yards of the granite which forms the borders of the basin. The occurrence of these marls so near the ancient margin may be explained by considering that, at the bottom of the ancient lake, no coarse ingredients were deposited in spaces inter- mediate between the points where rivers and torrents entered, but finer Fig. 177. THININSS Vertical strata of marl, at Champradelle, near Clermont. A. Granite. B. Space of 60 feet, in which no section is seen. ©. Green marl, vertical and inclined. D. White marl. mud only was drifted there by currents. The verticality of some of the beds in the above section bears testimony to considerable local disturb- ance subsequent to the deposition of the marls; but such inclined and vertical strata are very rare. 3. Limestone, travertin, oolite—Both the preceding members of the lacustrine deposit, the marls and grits, pass occasionally into limestone. Sometimes only concretionary nodules abound in them; but these, where there is an increase in the quantity of calcareous matter, unite into reg- ular beds. On each side of the basin of the Limagne, both on the west at Gan- nat, and on the east at Vichy, a white oolitic limestone is quarried. At 200 INDUSIAL LIMESTONE. (Ca. XV. Vichy, the oolite resembles our Bath stone in appearance and beauty; and, like it, is soft when first taken from the quarry, but soon hardens on exposure to the air. At Gannat, the stone contains land-shells and bones of quadrupeds. At Chadrat, in the hill of La Serre, the limestone is pisolitic, the small spheroids combining both the radiated and concen- tric structure. Indusial limestone-—There is another remarkable form of freshwater limestone in Auvergne, called “indusial,” from the cases, or indusiw, of eaddis-worms (the larvee of Phryganea); great heaps of which have been incrusted, as they lay, by carbonate of lime, and formed into a hard travertin. The rock is sometimes purely calcareous, but there is occa- sionally an intermixture of siliceous matter. Several beds of it are fre- quently seen, either in continuous masses, or in concretionary nodules, one upon another, with layers of marl interposed. The annexed drawing (fig. 178) will show the manner in which one of these indusial beds (a) is laid open at the surface, between the marls (6 6), near the base of the hill of Gergovia; and affords, at the same time, an example of the extent to which the lacustrine strata, which must once have filled a hollow, have been denuded, and shaped out into hills and valleys, on the site of the ancient lakes. ~ > S a WE, Re “& SARA SS EX a SSS —_ eS nip -it il lagi ini) S esa INSSSSSSS OSS SESS A OES SSS. SS ee. Bed of indusial limestone, interstratified with freshwater marl, near Clermont (Kleinschrod). We may often observe in our ponds the Phryganea (or Caddice-fly), mn its caterpillar state, covered with small freshwater shells, which they have the power of fixing to the outside of their tubular cases, in order, probably, to give them weight and strength. The individual figured in Cz. XV.] EOCENE PERIOD. 201 the annexed cut, which belongs to a species very abundant in England, has covered its case with shells of a small Planorbis. In the same manner a large species of caddis-worm, which swarmed in the Eocene lakes of Auvergne, was accustomed to attach to its dwelling the shells of a small spiral univalve of the genus Paludina. A hundred of these minute shells are some- times seen arranged around one tube, part of the central cavity of which is often empty, the rest being filled up with thin concentric layers of travertin. The cases have been thrown together confusedly, and often tlie, as in fig. 180, at right angles one to the other. When we consider Fig. 180. ie? vat a. Indusial limestone of Auvergne. b. Fossil Paludina magnified. that ten or twelve tubes are packed within the compass of a cubic inch, and that some single strata of this limestone are 6 feet thick, and may be traced over a considerable area, we may form some idea of the count- less number of insects and mollusca which contributed their integuments and shells to compose this singularly constructed rock. It is unnecessa- ry to suppose that the Phryganee lived on the spots where their cases are now found; they may have multiplied in the shallows near the margin of the lake, or in the streams by which it was fed, and their cases may have been drifted by a current far into the deep water. In the summer of 1837, when examining, in company with Dr. Beck, a small lake near Copenhagen, I had an opportunity of witnessing a beautiful exemplification of the manner in which the tubular cases of Auvergne were probably accumulated. This lake, called the Fuure-Soe, occurring in the interior of Seeland, is about twenty English miles in circumference, and in some parts 200 feet in depth. Round the shallow borders an abundant crop of reeds and rushes may be observed, covered with the indusiz of the Phryganea grandis and other species, to which shells are attached. The plants which support them are the bullrush, Scirpus lacustris, and common reed, Arundo phragmites, but chiefly the former. In summer, especially in the month of June, a violent gust of wind sometimes causes a current by which these plants are torn up by the roots, washed away, and floated off in long bands, more than a mile in length, into deep water. The Cypris swarms in the same lake; and calcareous springs alone are wanting to form extensive beds of indusial limestone, like those of Auvergne. * J believe that the British specimen here figured is P. rhombica, Linn. 202 LACUSTRINE STRATA—AUVERGNE. [Ca XV. 4, Gypseous marls—More than 50 feet of thinly laminated gypseous marls, exactly resembling those in the hill of Montmartre, at Paris, are worked for gypsum at St. Romain, on the right bank of the Allier. They rest onaseries of green cypridiferous marls which alternate with grit, the united thickness of this inferior group being seen, in a vertical section op the banks of the river, to exceed 250 feet. General arrangement, origin, and age of the freshwater formations of Auvergne.—the relations of the different groups above described can- not be learnt by the study of any one section; and the geologist who sets out with the expectation of finding a fixed order of succession may perhaps complain that the different parts of the basin give contradictory results. The arenaceous division, the marls, and the limestone, may ali be seen in some places to alternate with each other; yet it can by no means be affirmed that there is no order of arrangement. The sands, sandstone, and conglomerate constitute in general a littoral group; the foliated white and green marls, a contemporaneous central deposit ; and the limestone is for the most part subordinate to the newer portions of both. The uppermost marls and sands are more calcareous than the lower ; and we never meet with calcareous rocks covered by a consider- able thickness of quartzose sand or green marl. From the resemblance of the limestones to the Italian travertins, we may conclude that they were derived from the waters of mineral springs,—such springs as even now exist in Auvergne, and which may be seen rising up through the granite, and precipitating travertin. They are sometimes thermal, but this character is by no means constant. It seems that, when the ancient lake of the Limagne first began to be filled with sediment, no voleanic action had yet produced lava and scoriz on any part of the surface of Auvergne. No pebbles, therefore, of lava were transported into the lake,—no fragments of volcanic rocks im- bedded in the conglomerate. But at a later period, when a considerable thickness of sandstone and marl had accumulated, eruptions broke out, and lava and tuff were deposited, at some spots, alternately with the lacustrine strata. It is not improbable that cold and thermal springs, holding different mineral ingredients in solution, became more numerous during the successive convulsions attending this development of voleanie agency, and thus deposits of carbonate and sulphate of lime, silex, and other minerals were produced. Hence these minerals predominate in the uppermost strata. The subterranean movements may then have continued, until they altered the relative levels of the country, and caused the waters of the lakes to be drained off, and the farther accumulation of regular freshwater strata to cease. We may easily conceive a similar series of events to give rise to anal- ogous results in any modern basin, such as that of Lake Superior, for example, where numerous rivers and torrents are carrymg down the detritus of a chain of mountains into the lake. The transported mate- rials must be arranged according to their size and weight, the coarser near the shore, the finer at a greater distance from land; but in the Cz. XV] UPPER EOCENE STRATA. 208 gravelly and sandy beds of Lake Superior no pebbles of modern volcanic rocks can be included, since there are none of these at present in the district. If igneous action should break out in that country, and pro- duce lava, scorize, and thermal springs, the deposition of gravel, sand, and marl might still continue as before; but, in addition, there would then be an intermixture of volcanic gravel and tuff, and of rocks precip- itated from the waters of mineral springs. Although the freshwater strata of the Limagne approach generally to a horizontal position, the proofs of local disturbance are sufficiently numerous and violent to allow us to suppose great changes of level since the lacustrine period. We are unable to assign a northern barrier to the ancient lake, although we can still trace its limits to the east, west, and south, where they were formed of bold granite eminences. Nor need we be surprised at our inability to restore entirely the physical geography of the country after so great a series of volcanic eruptions; for it is by no means improbable that one part of it, the southern, for example, may haye been moved upwards bodily, while others remained at rest, or even suffered a movement of depression. Whether all the freshwater formations of the Limagne d’Auvergne belong to one period, I cannot pretend to decide, as large masses both of the arenaceous and marly groups are often devoid of fossils. Some of the oldest or lowest sands and marls may very probably be of Middle Eocene date. Much light has been thrown on the mammiferous fauna by the labors of MM. Bravard and Croizet, and by those of M. Pomel. The last-mentioned naturalist has pointed out the specific distinction of all, or nearly all, the species of mammalia from those of the gypseous series near Paris, although many of the forms are analogous to those of Eocene quadrupeds. The Cainotherium, for example, is not far removed from the Anoplotherium, and is, according to Waterhouse, the same as the genus Microtherium of the Germans. There are two species of marsupial animals allied to Didelphys, a genus also found in the Paris gypsum, and several forms of ruminants of extinct genera, such as Amphitragulas elegans of Pomel, which has been identified with a Rhenish species from Weisse- nau near Mayence, called by Kaup Dorcatherium nanum ; other associ- ated fossils, e. ¢., Microtherium Reuggeri, and a small rodent, Titanomys, are also specifically the same with mammalia of the Mayence basin. The Hyenodon, a remarkable carnivorous genus, is represented by more than one species, and the oldest representative of the genus Machairodus has been discovered in these beds in Auvergne. The first of these, Hy@nodon, also oceurs in the English Middle-Eocene marls of Hordwell cliff, Hamp- shire, considerably below the level of the Bembridge limestone, with Paleotheria. Upon the whole it is clear that a large portion of the Limagne rocks haye been correctly referred by French geologists to their Middle Tertiary, and to that part of it which is called Upper Eocene in this work. Cantal.—A_ freshwater formation, of about the same age and very analogous to that of Auvergne, is situated in the department of Haute 204 UPPER EOCENE STRATA—CANTAL. [Cm XV. Loire, near the town of Le Puy, in Velay; and another occurs near Aurillac, in Cantal. The leading feature of the formation last mentioned, as distinguished from those of Auvergne and Velay, is the immense abundance of silex associated with calcareous marls and limestone. The whole series may be separated into two divisions; the lower, com- posed of gravel, sand, and clay, such as might have been derived from the wearing down and decomposition of the granitic schists of the surrounding country ; the upper system, consisting of siliceous and calea- reous matls, contains subordinately gypsum, silex, and limestone. The resemblance of the freshwater limestone of the Cantal, and its accompanying flint, to the upper chalk of England, is very instructive, and well calculated to put the student upon his guard against rely- ing too implicitly on mineral character alone as a safe criterion of rela- tive age. When we approach Aurillac from the west, we pass over great heathy plains, where the sterile mica-schist is barely covered with vegetation. Near Ytrac, and between La-Capelle and Viscamp, the surface is strewed over with loose broken flints, some of them black in the interior, but with a white external coating; others stained with tints of yellow and red, and in appearance precisely like the flint gravel of our chalk districts. When heaps of this gravel have thus announced our approach to a new formation, we arrive at length at the escarpment of the lacustrine beds, At the bottom of the hill which rises before us, we see strata of clay and sand, resting on mica-schist ; and above, in the quarries of Belbet, Leybros, and Bruel, a white limestone, in horizontal strata, the surface of which has been hollowed out into irregular furrows, since filled up with broken flint, marl, and dark vegetable mould. In these cavities we recog- nize an exact counterpart to those which are so numerous on the fur- rowed surface of our own white chalk. Advancing from these quarries along a road made of the white limestone, which reflects as glaring a light in the sun as do our roads composed of chalk, we reach, at length, in the neighborhood of Aurillac, hills of limestone and calcareous marl, in horizontal strata, separated in some places by regular layers of flint in nodules, the coating of each nodule being of an opaque white color, like the exterior of the flinty nodules of our chalk. The abundant supply both of siliceous, calcareous, and gypseous mat- ter, which the ancient lakes of France received, may have been connected with the subterranean volcanic agency of which those regions were so long the theatre, and which may have impregnated the springs with min- eral matter, even before the great outbreak of lava. It is well known that the hot springs of Iceland, and many other countries, contain silex in'solu- tion ; and it has been lately affirmed, that steam at a high temperature is capable of dissolving quartzose rocks without the aid of any alkaline or other flux.* Warm water charged with siliceous matter would immedi- ately part with a portion of its silex, if its temperature was lowered by mixing with the cooler waters of a lake. * See Proceedings of Royal Soe., No. 44, p. 233. Cu. XV.] SLOWNESS OF DEPOSITION. 205 A hasty observation of the white limestone and flint of Aurillac might convey the idea that the rock was of the same age as the white chalk of Europe; but when we turn from the mineral aspect and composition to the organic remains, we find in the flints of the Cantal seed-vessels of the freshwater Chara, instead of the marine zoophytes so abundant in chalk flints; and in the limestone we meet with shells of Zimnea, Planorbis, and other lacustrine genera. Proofs of gradual deposition—Some sections of the foliated marls in the valley of the Cer, near Aurillac, attest, in the most unequivocal man- ner, the extreme slowness with which the materials of the lacustrine series were amassed. In the hill of Barrat, for example, we find an assemblage of caleareous and siliceous marls; in which, for a depth of at least 60 feet, the layers are so thin, that thirty are sometimes contained in the thickness of an inch; and when they are separated, we see preserved in every one of them the flattened stems of Chare, or other plants, or some- times myriads of small Paludine and other freshwater shells. These minute foliations of the marl resemble precisely some of the recent lamina- ted beds of the Scotch marl lakes, and may be compared to the pages of a book, each containing a history of a certain period of the past. The different layers may be grouped together in beds from a foot to a foot and a halfin thickness, which are distinguished by differences of composi- tion and color, the tints being white, green, and brown. Occasionally there is a parting layer of pure flint, or of black carbonaceous vegetable matter, about an inch thick, or of white pulverulent marl. We find sev- eral hills in the neighborhood of Aurillac composed of such materials, for the height of more than 200 feet from their base, the whole sometimes covered by rocky currents of trachytic or basaltic lava.* Thus wonderfully minute are the separate parts of which some of the most massive geological monuments are made up! When we desire to classify, it is necessary to contemplate entire groups of strata in the aggre- gate; but if we wish to understand the mode of their formation, and to explain their origin, we must think only of the minute subdivisions of which each mass is composed. We must bear in mind how many thin leaf-like seams of matter, each containing the remains of myriads of tes- tacea and plants, frequently enter into the composition of a single stratum, and how vast a succession of these strata unite to form a single group! We must remember, also, that piles of volcanic matter, like the Plomb du Cantal, which rises in the immediate neighborhood of Aurillac, are themselyes equally the result of successive accumulation, consisting of reiterated sheets of lava, showers of scorie, and ejected fragments of rock.—Lastly, we must not forget that continents and mountain-chains, colossal as are their dimensions, are nothing more than an assemblage of many such igneous and aqueous groups, formed in succession during an indefinite lapse of ages, and superimposed upon each other. Bourdeauz, Aiz, &&—The Upper Eocene Strata in the Bourdeaux * Lyell and Murchison; sur les Dép6ts Lacustres Tertiaires du Cantal, &c. Ann, des Sci. Nat. Oct. 1829. 206 UPPER EOCENE OF NEBRASKA, U. 8. [Cu. XV. basin are represented, according to M. Raulin, by the Falun de Leognan, and the underlying limestone of St. Macaire. By many, however, the upper of these, or the Leognan beds, are considered to be no older than the faluns of Touraine. The freshwater strata of Aix-en-Provence are probably Upper Eocene ; also the tertiary rocks of Malta, Crete, Cerigo, and those of many parts of Greece and other countries bordering the Mediterranean. Nebraska, United States—In the territory of Nebraska, on the Upper Missouri, near the Platte River, lat. 42° N., a tertiary formation occurs, consisting of white limestone, marls, and siliceous clay, described by Dr. D. Dale Owen,* in which many bones of extinct quadrupeds, and of chelonians of land or freshwater forms, are met with. Among these, Dr. Leidy recognizes a gigantic Palwotherium, larger than any of the Parisian species ; several species of the genus Orcodon, Leidy, uniting the characters of pachyderms and ruminants; Hucrotaphus, another new genus of the same mixed character; two species of rhinoceros of the sub-genus Acerotherium, an Upper Eocene form of Europe before men- tioned; two of Archeotherium, a pachyderm allied to Cheropotamus and Hyracotherium ; also Pebrothertum, an extinct ruminant allied to Dorcatherium, Kaup; also Agriochegus of Leidy, a ruminant allied to Merycopotamus of Falconer and Cautley; and, lastly, a large car- nivorous animal of the genus Machairodus, the most ancient example of which in Europe occurs in the Upper Eocene beds of Auvergne. The turtles are referred to the genus Testudo, but have some affinity to Hmys. On the whole, this formation has, I believe, been correctly referred by American writers to the Eocene period, in conformity with the classification adopted by me, but would, I conceive, be called Lower Miocene by those who apply that term to all strata newer than the Paris gypsum. * David Dale Owen, Geol Survey of Wisconsin, dc.; Philad, 1852. Cu, XVI] MIDDLE EOCENE FORMATIONS. 207 CHAPTER XVI. MIDDLE AND LOWER EOCENE FORMATIONS. Middle Eocene strata of England—Fluvio-marine series in the Isle of Wight and Hampshire—Successive groups of Eocene Mammalia—Fossils of Barton Clay— Shells, mummulites, fishes, and reptiles of the Bagshot and Bracklesham beds —Lower Eocene strata of England—Fossil plants and shells of the London Clay proper—Strata of Kyson in Suffolk—Fossil monkey and opossum—Plastic clays and sands—Thanet sands—Middle Eocene formations of France—Gyp- seous series of Montmartre and extinct quadrupeds—Caleaire grossier—Milio- lites—Lower Eocene in France—Nummulitic formations of Europe and Asia— Their wide extent ; referable to the Middle Eocene period—Kocene strata in the United States—Section at Claiborne, Alabama—Colossal cetacean—Orbitoid limestone—Burr-stone. Tue strata next in order in the descending series are those which I term Middle Eocene. In the accompanying map, the position of several Eocene areas is pointed out, such as the basin of the Thames, part of Fig. 181. Map of the principal tertiary basins of the Eocene period. de Se ZL Lisoet ZD a —_» Hypogene rocks and strata Eocene formations, older than the Devonian or Old Red series, N.B. The space left blank is occupied by secondary formations from the Devyoni: 1d sandstone to the chalk inclusive. ! y yi Mego ree Hampshire, part of the Netherlands, and the country round Paris. The three last-mentioned areas contain some marine and freshwater formations, which have been already spoken of as Upper Eocene, but their superficial extent in this part of Europe is insignificant. ENGLISH MIDDLE EOCENE FORMATIONS. The following table will show the order of succession of the strata found in the Tertiary areas, commonly called the London and Hampshire basins. (See also Table, p. 104, et seq.) 208 ENGLISH MIDDLE EOCENE FORMATIONS. ([Ca. XVL- UPPER EOCENE, Thickness, A. Hempstead beds, Isle of Wight, see above, p.192 - - 140 feet. MIDDLE EOCENE. B. 1. Bembridge Series,—North coast of Isle of Wight =, - 120 B. 2. Osborne or St. Helen’s Series—ibid. - - - - 100 B. 3, Headon Series,—Isle of Wight, and Hordwell Cliff, Hants - 170 B. 4. Headon Hill sands and Barton Cleyrelle of Wight: and Barton Cliff, Hants - - 300 B. 5. Bagshot and Bracklesham Sands ana Clays, Tends ind Hants basins: = 9.2) §8 48 Sabet eee) cy a or eg 08 LOWER EOCENE, C. 1. London Clay proper and Bognor beds,—London and Hants basins - - cl 350 to 500 C. 2. Plastic and Mottled eee Aa Bande (Woolwich = eating series),—London and Hants basins - - - - 100 C. 8. Thanet Sands,—Reculvers, Kent, and Eastern Hart of London basin - - - - - : eG - - 90 The true place of the Bagshot sands, B. 5 in the above series, and of the Thanet sands, C. 3, was first accurately ascertained by Mr. Prestwich in 1847 and 1852. The true relative position of the Hempstead beds, A of the Bembridge, B. 1, and of the Osborne or St. Helen’s series, B. 2, were not made out in a satisfactory mamner till Professor Forbes studied them in detail in 1852. Bembridge series, B. 1—These beds are above 100 feet thick, and, as before stated (p. 187), pass upwards into the Hempstead beds, with which they are conformable, near Yarmouth, in the Isle of Wight. They con- sist of marls, clays, and limestones of freshwater, brackish, and marine origin. Some of the most abundant shells, as Cyrena semistriata var., and Paludina lenta (fig. 175, p. 193), are common to this and to the overlying Hempstead series. The following are the subdivisions described by Professor Forbes : a, Upper marls, distinguished by the abundance of Melania turritissima, Forbes (fig. 182). Fig. 183. Melania turritissima, Forbes. Fragment of Carapace of Trionyx. Bembridge. Bembridge Beds, Isle of Wight. 6. Lower marl, characterized by Cerithium mutabile, Cyrena pulchra, &., and by the remains of Trionyzx (see fig. 183). c. Green marls, often abounding in a peculiar species of oyster, and accompanied ~ by Cerithia, Mytili, an Arca, a Nucula, &c. d. Bembridge limestones, compact cream-colored limestones alternating with Cx. XVL] FLUVIO-MARINE SERIES IN ISLE OF WIGHT. 209 shales and marls, in all of which land-shells are common, especially at Sconce, near Yarmouth, and have been described by Mr. Edwards, The Bulimus ellip- ticus (fig. 184), and Helix occlusa (fig. 185), are among its best-known land- Fig. 186. Bulimus ellipticus, Sow. Helix occlusa, Edwards, Paludina orbicularis, Bembridge. Bembridge Limestone, Sconce Limestone, half natural size. Isle of Wight. shells. Paludina orbicularis (fig. 186) is also of frequent occurrence. One of the bands is filled with a little globular Paludina. Among the freshwater Fig. 187. Fig. 188. Fig. 189. Plunorbis discus, Edwards. Bem- Lymmnea longiscata, Brard. Chara tuberculata. bridge. 4 diam. Bembridge Lime- stone, I. of Wight. pulmonifera, Lymnea longiscata (fig. 188) and Planorbis discus (fig. 187) are the most generally distributed: the latter represents or takes the place of the Planorbis euomphalus (see fig. 192), of the more ancient Headon series. Chara tuberculata (fig, 189), is the characteristic Bembridge gyrogonite. From this formation on the shores of Whitecliff Bay, Dr. Mantell ob- tained a fine specimen of a fan palm, Plabellaria Lamanonis, Brong., a plant first obtained from beds of corresponding age in the suburbs of Paris. - The well-known building-stone of Binstead, near Ryde, a lime- stone with numerous hollows caused by Cyrene which have disappeared and left the moulds of their shells, belongs to this subdivision of the Bembridge series, In the same Binstead stone Mr. Pratt and the Rey. Darwin Fox first discovered the remains of mammalia char- acteristic of the gypseous series of Paris, as Palwotherium magnum 14 210 FLUVIO-MARINE SERIES IN ISLE OF WIGHT. [Ca. XV1L. (fig. 191), P. medium, P. minus, P. mimimum, P. Bigwig: eurtum, P. crassum ; also Anoplotherium commune (fig. 190), A. secundarium, Dichobune cervinum, and Cheropotamus Cuvieri. The genus Paleothere, above alluded to, resembled the living tapir in the form of the head, and in haying a short proboscis, but its molar teeth were more like those of the rhinoceros (see fig. 5 i Lower Molar tooth 190). Paleotherium magnum was of the size of a nat, size. . Anoplothertum com- horse, three or four feet high. The annexed woodcut 4 (fig. 191) is one of the restorations which Cuvier at- tempted of the outline of the living animal, derived from the study of the mune. Binstead, Isle of Wight. Fig. 191. Paleotherium magnum, Cuvier. entire skeleton. As the vertical range of particular species of quadrupeds, so far as our knowledge extends, is far more limited than that of the tes- tacea; the occurrence of so many species at Binstead, agreeing with fossils of the Paris gypsum, strengthens the evidence derived from shells and plants of the synchronism of the two formations. Osborne or St. Helen’s series, B. 2.—This group is of fresh and brack- ish-water origin, and very variable in mineral character and thickness. Near Ryde, it supplies a freestone much used for building, and called by Professor Forbes the Nettlestone grit. In one part ripple-marked flag- stones occur, and rocks with fucoidal markings. The Osborne beds are distinguished by peculiar species of Paludina, Melania, and Melanopsis, as also of Cypris and the seeds of Chara. Headon series, B. 3—These beds are seen both at the east and west extremities of the Isle of Wight, and also in Hordwell Cliffs, Hants. Everywhere Planorbis euomphalus (fig. 192) characterizes the freshwater deposits, just as the allied form, P. discus (fig. 187) does the Bembridge limestone. The brackish-water beds contain Patomomya plana, Cerithium mutabile, and C. cinctum (fig. 44, p. 30), and the marine beds Venus (or Cytherea) incrassata, a species common to the Limburg beds and Grés de Fontainebleau, or the Upper Eocene series. The prevalence of ina me Cx. XVI] SHELL OF THE HEADON SERIES. 211 salt-water remains is most conspicuous in some of the central parts of the formation. Mr. T. Webster, in his able memoirs on the Isle of Wight, Fig. 192, Fig. 193. Planorbis ewomphatlus, Sow. Heli labyrinthica, Say. Headon Hill, Isle of Wight: Headon Hill. 3 diam, and Hordwell Cliff, Hants—also recent. first separated the whole into a lower freshwater, an upper marine, and an upper freshwater division. Among the shells which are widely distributed through the Headon series are Weritina concava (fig. 194), Lymnea caudata (fig. 195), and Cerithium concavum (fig. 196), Helix labyrinthica, Say (fig. 1938), a Fig. 194, Neritina concava. Lymnea caudata, ' Cerithium concavum. Headon Series, Headon Beds, Headon Series, land-shell now inhabiting the United States, was discovered in this series by Mr. Wood in Hordwell Cliff. It is also met with in Headon Hill, in the same beds. At Sconce, in the Isle of Wight, it occurs in the newer Bembridge series, and affords a rare example of an Eocene fossil of a spe- cies still living, though, as usual in such cases, having no local connection with the actual geographical range of the species. The lower and middle portion of the Headon series is also met with in Hordwell Cliff (or Hordle, as it is often spelt), near Lymington, Hants, where the organic remains have been studied by Mr. Searles Wood, Dr. Wright, and the Marchioness of Hastings. To the latter we are indebted for a detailed section of the beds,* as well as for the discovery of a variety of new species of fossil mammalia, chelonians, and fish ; also for first call- ing attention to the important fact that these vertebrata differ specifically from those of the Bembridge beds. Among the abundant shells of Hord- well are Paludina lenta and various species of Lymneus, Planorbis, Melania, Cyclas, and Unio, Potomomya, Dreissena, &e. * Bulletin, Soc. Géol. de France, 1852, p. 191. 212 FLUVIO-MARINE SERIES IN HAMPSHIRE. ([Cxs. XVL Among the chelonians we find a species of mys, and no less than six species of Zrionyx ; among the saurians an alligator and a crocodile ; among the ophidians two species of land-snakes (Paleryx, Owen) ; and among the fish Sir P. Egerton and Mr. Wood have found the jaws, teeth, and hard shining scales of the genus Lepidosteus or bony pike of the American rivers. This same genus of freshwater ganoids has also been met with in the Hempstead beds of the Isle of Wight. The bones of several birds have been obtained from Hordwell, and the remains of quad- rupeds. The latter belong to the genera Paloplotherium of Owen, Ano- plotherium, Anthracotherium, Dichodon of Owen (a new genus discovered by Mr. A. H. Falconer), Dichobune, Spalacodon, and Hycnodon. The latter offers, I believe, the oldest known example of a true carnivorous mammal in the series of British fossils, although I attach very little the- oretical importance to the fact, because herbivorous species are those most easily met with in a fossil state in all saye cavern deposits. In another point of view, however, this fauna deseryes notice. Its geological position is considerably lower than that of the Bembridge or Montmartre beds, from which it differs almost as much in species as it does from the still more ancient fauna of the Lower Eocene beds to be mentioned in the sequel. It therefore teaches us what a grand succession of distinct assemblages of mammalia flourished on the earth during the Eocene period. Many of the marine shells of the brackish-water beds of the above series, both in the Isle of Wight and Hordwell Cliff, are common to the underlying Barton clay; and, on the other hand, there are some fresh- water shells, such as Cyrena obovata, which are common to the Bem- bridge beds, notwithstanding the intervention of the St. Helen’s series. The white and green marls of the Headon series, and some of the accom- panying limestones, often resemble the Eocene strata of France in mineral character and color in so striking a manner, as to suggest the idea that the sediment was derived from the same region or produced contempo- raneously under very similar geographical circumstances. Both in Hordwell Cliff and in the Isle of Wight, the Headon beds rest on white sands, the upper member of the Barton series, B. 4, next to be mentioned. Headon Hill sands and Barton clay, B. 4 (Table, p. 208).—In one of the upper and sandy beds of this formation Dr. Wright found Chama squamosa in great plenty. The same sands contain impressions of many marine shells (especially in Whitecliff Bay) common to the upper Bagshot sands afterwards to be described. The underlying Barton clay has yielded about 209 marine shells, more than half of ithem, according to Mr. Prestwich, peculiar; and only Fig. 197. ‘eleven common to the London clay proper (C. 1, p. 208), Chama : . . 5 équamosa, being in the proportion of only 5 per cent. On the other Barton. hand, 70 of them agree with the shells of the calcaire :grossier of France. It is nearly a century since Brander published, in Cx. XVI] FOSSILS OF THE BARTON CLAY. 213 1766, an account of the organic remains collected from these Barton ana Hordwell cliffs, and his excellent figures of the shells then deposited in the British Museum are justly admired by conchologists for their accuracy. SHELLS OF THE BARTON CLAY, HANTS. Certain foraminifera called Nummulites begin, when we study the tertiary formations in a descending order, to make their first appearance Fig. 198. Fig. 199, Fig, 200. Fig. 201. Typhis pungens. Voluta athleta. Barton ES ed and Bracklesham. Terebellum fusi- Terebellum con- Cardita globosa. Crassatella sulcata, Jorme. Barton volutwm. Lam. and Bracklesham. Seraphs convolu- twim, Montf. in these Barton beds. A small species called Vummulites variolaria is found both on the Hampshire coast and in beds of the same age in Whitecliff Bay, in the Isle of Wight. Several marine shells, such as Corbula pisum, are common to the Barton beds and the Hempstead or Upper Eocene series, and a still greater number, as before stated, are common to the Headon series. Bagshot and Bracklesham beds, B. 5—The Bagshot beds, consisting chiefly of siliceous sand, occupy extensive tracts round Bagshot, in Surrey, and in the New Forest, Hampshire. They may be separated into three divisions, the upper and lower consisting of light yellow sands, and the central of dark green sands and brown clays, the whole reposing on the London clay proper.* The uppermost division is probably of about the same age as the Barton series. Although the Bagshot beds are usually * Prestwich, Quart. Geol, Journ, vol. iii. p, 886. 214 EOCENE—BAGSHOT SANDS. | [Cu. XVI. devoid of fossils, they contain marine shells in some places, among which Venericardia planicosta (see fig. 206) is abundant, with Turritella sul- cifera and Nummulites levigata. (See fig. 210, p. 215.) Fig. 206. Venericardia planicosta, Lam. Cardita planicosta, Deshayes. At Bracklesham Bay, near Chichester, in Sussex, the characteristic shells of this member of the Eocene series are best seen; among others, the huge Cerithium giganteum, so conspicuous in the calcaire grossier of Paris, where it is sometimes 2 feet in length. The volutes and cowries of this formation, as well as the lunulites and corals, seem to favor the idea of a warm climate having prevailed, which is borne out by the discovery of a serpent, Paleophis typheus (see fig. 207), exceeding, according to Fig. 207. Paleophis typhous, Owen; an Eocene sea-serpent. Bracklesham. | a, 0. Vertebra, with long neural spine preserved. c. Two yertebre in natural articulation. Prof. Owen, 20 feet in length, and allied in its osteology to the Boa, Py thon, Coluber, and Hydrus. The compressed form and diminutive size of certain caudal vertebre indicate so much analogy with Hydrus as to in- duce the Hunterian professor to pronounce this extinct ophidian to have been marine.* He had previously combated with much success the evi- dence advanced to prove the existence in the Northern Ocean of huge sea- serpents in our own times, but he now contends for the former existence in the British Eocene seas, of less gigantic serpents, when the climate was * Palzont. Soc. Monograph. Rept. pt. ii. p. 61. Cu. XVI] BRACKLESHAM BEDS. 215° probably more genial; for amongst the companions of the sea-snake of Bracklesham was an extinct Gavial (Gavialis Dixoni, Owen), and numer- ous fish, such as now frequent the seas of warm latitudes, as the sword-fish (see fig. 208), and gigantic rays of the genus Myliobates (see fig. 209). Fig. 208. Prolonged premaxillary bone or “ sword” of a fossil sword-fish (Calorhynchus), Brackle- sham. Dixon’s Fossils of Sussex, pl. 8. Dental plates of Myliobates Edwardsi. Nummulites (Nummularia) levigata, Bracklesham Bay. Ibid. pl. 8. Bracklesham. Ibid. pl. 8. a. Section of the nummulite. b. Group, with an individual showing the exterior of the shell. The teeth of sharks also, of the genera Carcharodon, Otodus, Lamna, Galeocerdo, and others, are abundant. (See figs. 211, 212, 213, 214.) Fig. 211, Fig. 212. Fig, 213. Fig. 214 Carcharodos veterodon, Agass. Otodus obliquus, Agass. Lamna elegans, Galeocerdo latidens, Agass, Agass. Teeth of sharks from Bracklesham Bay. The Vummulites levigata (see fig. 210), so characteristic of the lower beds of the calcaire grossier in France, where it sometimes forms stony layers, as near Compiegne, is very common at Bracklesham, together with NV. scabra and NV. variolaria. Out of 193 species of testacea procured from the Bagshot and Bracklesham beds in England, 126 occur in the ealeaire grossier in France. It was clearly therefore coeval with that part of the Parisian series more nearly than with any other. 216 LOWER EOCENE STRATA OF ENGLAND. [Cu. XVL MARINE SHELLS OF BRACKLESHAM BEDS. Fig. 216. Fig. 217. Fig. 218. Fig. 219. Pleurotoma atten- Voluta la- Turritella, Lucina serrata, Dixon. Conus deper- uata, Sow. trella, Lam. Se uEaNG, Magnified. ditus. am. LOWER EOCENE FORMATIONS OF ENGLAND. London Clay proper (C. 1, Table, p. 208).—This formation underlies the preceding, and consists of tenacious brown and bluish-gray clay, with layers of concretions called septaria, which abound chiefly in the brown clay, and are obtained in sufficient numbers from sea-cliffs near Harwich, and from shoals off the Essex coast, to be used for making Ro- man cement. The principal localities of fossils in the London clay are Highgate Hill, near London, the island of Sheppey, and Bognor in Hamp- shire. Out of 133 fossil shells, Mr. Prestwich found only 20 to be com- mon to the calcaire grossier (from which 600 species have been obtained), while 33 are common to the “ Lits Coquilliers” (p. 228), in which only 200 species are known in France. We may presume, therefore, that the London clay proper is older than the calcaire grossier. This may perhaps remove a difficulty which M. Adolphe Brongniart has experienced when comparing the Eocene Flora of the neighborhoods of London and Paris. The fossi. species of the island of Sheppey, he observes, indicate a much more tropical climate than the Eocene Flora of France. Now the latter has been derived principally from the gypseous series, and resembles the vegetation of the borders of the Mediterranean Fig. 220, rather than that of an equatorial region ; whereas the older flora of Sheppey belongs to an antece- dent epoch, separated from the period of the Paris gypsum by all the calcaire grossier and Bagshot series—in short, by the whole nummulitic forma- tion properly so called. Mr. Bowerbank, in a valuable publication on the fossil fruits and seeds of the island of Sheppey, near London, has described no less than thirteen fruits of palms of the recent type Vipa, now only = Sow : Nipadites ellipticus, Bow. found in the Molucca and Philippine islands and _Fossil palm of Sheppey. in Bengal (see fig. 220). In the delta of the Ganges, Dr. Hooker ob- served the large nuts of Wipa fruticans floating in such numbers in the various arms of that great river, as to obstruct the paddle-wheels of Cu. XVI] FOSSILS OF THE LONDON CLAY. 217 steamboats. These plants are allied to the cocoa-nut tribe on the one side, and on the other to the Pandanus, or screw-pine. The fruits of other palms besides those of the cocoa-nut tribe are also met with in the clay of Sheppey; also three species of Anona, or custard-apple; and eucurbitaceous fruits (of the gourd and melon family) are in considera- ble abundance. Fruits of various species of Acacia are in profusion, and these, although less decidedly tropical, imply a warm climate. The contiguity of land may be inferred not only from these vegetable productions, but also from the teeth and bones of crocodiles and turtles, since these creatures, as Dr. Conybeare has remarked, must have resorted to some shore to lay their eggs. Of turtles there were numerous species referred to extinct genera. These are, for the most part, not equal in size to the largest living tropical turtles. A sea-snake, which must have been 13 feet long, of the genus Paleophis before mentioned (p. 214), has also been described by Professor Owen from Sheppey, of a different species from that of Bracklesham. A true crocodile, also, Crocodilus toliapicus, and another saurian more nearly allied to the gavial, accompany the above fossils ; also.the relics of several birds and quadrupeds. One of these last belongs to the new genus Hyracotherium of Owen, allied to the Hyrax, Hog, and Cheropotamus ; another is a Lophiodon ; a third, a pachyderm called Coryphodon eocenus by Owen, larger than any existing tapir. All these animals seem to have inhabited the banks of the great river which floated down the Sheppey fruits. They imply the existence of a mammiferous fauna antecedent to the period when nummulites flour- ished in Europe and Asia, and therefore before the Alps, Pyrenees, and other mountain-chains now forming the backbones of great continents, were raised from the deep; nay, even before a part of the constituent rocky masses now entering into the central ridges of these chains had been deposited in the sea, The marine shells of the London clay confirm -the inference derivable from the plants and reptiles in favor of a high temperature. Thus many species of Conus and Voluta occur, a large Cyprea, C. oviformis, a very large Rostellaria (fig. 223), a species of Cancellaria, six species of Vau- tilus (fig. 225), besides other cephalopoda of extinct genera, one of the most remarkable of which is the Belosepia* (fig. 226). Among many characteristic bivalve shells are Leda amygdaloides (fig. 227) and Azinus angulatus (fig. 228), and among the Radiata a star-fish called Astropec- ten (fig. 229). These fossils are accompanied by a sword-fish (Zetrapterus priscus, Agassiz), about 8 feet long, and a saw-fish (Pristis bisulcatus, Ag.), about 10 feet in length; genera now foreign to the British seas, On the whole, no less than 50 species of fish have been described by M. Agassiz from these beds in Sheppey, and they indicate, in his opinion, a warm climate. * For description of Eocene Cephalopoda, see Monograph by F. E. Edwards, Palzontograph. Soc. 1849, 218 FOSSIL SHELLS OF THE LONDON CLAY. [Cs XVI. FOSSIL SHELLS OF THE LONDON CLAY. Fig. 222. Voluta nodosa, Sow. Phorus extensus, Highgate. Sow. Highgate. Rostellaria macroptera, Sow. One- third of nat. size; also found in the Barton clay. Fig. 226. Aluria eiczac, Brown and Edwards. Belosepia sepioidea. De Blainy. Syn. Nautilus ziczac, Sow. London clay. Sheppey. London clay. Sheppey. Fig, 297, Fig. 228. Leda amygdaloides. Avinus angulatus. London Astropecten crispatus, Highgate. clay. Hornsea. E. Forbes. Sheppey. Strata of Kyson in Suffolk—At Kyson, a few miles east of Wood- bridge, a bed of Eocene clay, 12 feet thick, underlies the red crag. Beneath it is a deposit of yellow and white sand, of considerable interest, im consequence of many peculiar fossils contained in it. Its geological position is probably the lowest part of the London clay proper. In this Ca. XVI] . STRATA OF KYSON IN SUFFOLK. 219 sand has been found the first example of a fossil quadrumanous animal discovered in Great Britain, namely, the teeth and Fig. 230. part of a jaw, shown by Professor Owen to belong 2 Pee to a monkey of the genus Macacus (see fig. 230). The mammiferous fossils, first met with in the Molar of monkey (Macacus), same bed, were those of an opossum (Didelphys) (see fig. 231), and an insectivorous bat (fig. 232), together with many teeth of fishes of the shark family. Mr. Colchester in 1840 obtained Fig. 281. other mammalian relics from Kyson, among which Professor Owen has recognized several teeth of the genus Hyracotheriwm, and the ver- ttebre of a large serpent, probably a Paleophis. As the remains both of the Hyracotheriwm and a Paleophis were afterwards met with in the Lon- ees ence don clay, as before remarked, these fossils con- firmed the opinion previously entertained, that the Kyson sand belongs to the Eocene period. The Macacus, therefore, constitutes the first exam- ple of any quadrumanous animal occurring instrata |, op insectivorous bats so old as the Eocene, or in a spot so far from the twice nat, size. equator as lat. 52° N. It was not until after the Pron eo as year 1836 that the existence of any fossil quadrumana was brought to light. Since that period they have been discovered in France, India, and Braail. Plastic or mottled clays and sands (C. 2, p. 208).—The clays called plastic, which lie immediately below the London clay, received their name originally in France from being often used in pottery. Beds of the same age (the Woolwich and Reading series of Prestwich) are used for the like purposes in England.t No formations can be more dissimilar on the whole in mineral char- acter than the Eocene deposits of England and Paris; those of our own island being almost exclusively of mechanical origin,—accumulations of mud, sand, and pebbles; while in the neighborhood of Paris we find a great succession of strata composed of limestones, some of them siliceous, and of crystalline gypsum and siliceous sandstone, and sometimes of pure flint used for millstones. Hence it is by no means an easy task to institute an exact comparison between the various members of the English and French series, and to settle their respective ages. It is clear that, on the sites both of Paris and London, a continual change was going on in the fauna and flora by the coming in of new species and the dying out of others; and contemporaneous changes of geographical conditions were also in progress in consequence of the rising and sinking of the land and bottom of the sea. A particular subdivision, therefore, of time was Fig. 232. * Annals of Nat. Hist. vol. iv. No. 23, Nov. 1839. + Prestwich, Water-bearing strata of London, 1851. 220 LOWER EOCENE STRATA OF ENGLAND. [Ca. XVL occasionally represented in one area by land, in another by an estuary, in a third by the sea, and even where the conditions were in both areas of a . marine character, there was often shallow water in one, and deep sea in another, producing a want of agreement in the state of animal life, But in regard to that division of the Eocene series which we have now under consideration, we find an exception to the general rule, for, whether we study it in the basins of London, Hampshire, or Paris, we recognize everywhere the same mineral character. This uniformity of aspect must be seen in order to be fully appreciated, since the beds consist simply of sand, mottled clays, and well-rolled flint pebbles, derived from the chalk, and varying in size from that of a pea to an egg. These strata may be seen in the Isle of Wight in contact with the chalk, or in the London basin, at Reading, Blackheath, and Woolwich. In some of the lowest of them, banks of oysters are observed, consisting of Ostrea bellovacina, so common in France in the same relative position, and Osirea edulina, scarcely distinguishable from the living eatable species. In the same beds at Bromley, Dr. Buckland found one large pebble to which five full-grown oysters were affixed, in such a manner as to show that they had commenced their first growth upon it, and remained attached to it through life. In several places, as at Woolwich on the Thames, at New Haven in Sussex, and elsewhere, a mixture of marine and freshwater testacea dis- tinguishes this member of the series. Among the latter, Milania inqui- nata (see fig. 234) and Cyrena cuneiformis (see fig. 233) are very come Fig. 234. Cyrena cuneiformis, Min. Con. Melania inquinata, Des. Nat. size. Natural size. Syn. Cerithium melanoides, Min. Con. mon, as in beds of corresponding age in France. They clearly indicate points where rivers entered the Eocene sea. Usually there is a mixture of brackish, freshwater, and marine shells, and sometimes, as at Woolwich, Ca. XVI] PLASTIC CLAYS AND SANDS. 221 proofs of the river and the sea having successively prevailed on the same spot. At New Charlton, in the suburbs of Woolwich, Mr. De la Conda- mine discovered in 1849, and pointed out to me, a layer of sand asso- ciated with well-rounded flint pebbles in which numerous individuals of the Cyrena tellinella were seen standing endwise with both their valves united, the posterior extremity of each shell being uppermost, as would happen if the mollusks had died in their natural position. I have de- seribed* a bank of sandy mud, in the delta of the Alabama river at Mobile, on the borders of the Gulf of Mexico, where in 1846 I dug out at low tide specimens of living species of Cyrena and of a Gnathodon, which were similarly placed with their shells erect, or in a position which enables the animal to protrude its siphon upwards, and draw in or reject water at pleasure. The water at Mobile is usually fresh, but sometimes brackish. At Woolwich a body of river water must have flowed permanently into the sea where the Cyrene lived, and they may have been killed suddenly by an influx of pure salt water, which invaded the spot when the river was low, or when a subsidence of land took place. ‘Traced in one direction, or eastward towards Herne Bay, the Woolwich beds assume more and more of a marine character ; while in an opposite, or southwestern direction, they become, as near Chelsea and other places, more freshwater, and contain Unio, Paludina, and layers of lignite, so that the land drained by the ancient river seems clearly to have been to the southwest of the present site of the metropolis. Before the minds of geologists had become familiar with the theory of the gradual sinking of land, and its conversion into sea at different pe- riods, and the consequent change from shallow to deep water, the fresh- water and littoral character of this inferior group appeared strange and anomalous. After passing through hundreds of feet of London clay, proved by its fossils to have been deposited in deep salt water, we arrive at oeds of fluviatile origin, and in the same underlying formation masses of shingle, attaining at Blackheath, near London, a thickness of 50 feet, indicate the proximity of land, where the flints of the chalk were rolled into sand and pebbles, and spread continuously over wide spaces. Such shingle always appears at the bottom of the series, whether in the Isle of Wight, or in the Hampshire or London basins. It may be asked why they did not constitute simply narrow littoral zones, such as we might look for on an ancient sea-shore. In reply, Mr. Prestwich has suggested that such zones of shingle may have been slowly formed on a large scale at the period of the Thanet sands (C. 3, p. 208), and while the land was sinking the well-rolled pebbles may have been dispersed simultaneously over considerable areas, and exposed during gradual submergence to the action of the waves of the sea, aided occasionally by tidal currents and river floods. Thanet sands (C. 3, p. 208).—The mottled or plastic clay of the * Second Visit to the United States, vol. ii, p. 104. 222 EOCENE STRATA IN FRANCE. [Cu XVI. Isle of Wight and Hampshire is often seen in actual contact with the chalk, constituting in such places the lowest member of the British Eo- cene series. But in other points another formation of marine origin, characterized by a somewhat different assemblage of organic remains, has been shown by Mr. Prestwich to intervene between the chalk and the Woolwich series. For these beds he has proposed the name of “Thanet sands,” because they are well seen in the Isle of Thanet, in the northern part of Kent, and on the sea-coast between Herne Bay and the Reculvers, where they consist of sands with a few concretionary masses of sandstone, and contain among other fossils Pholadomya cuneata, Cyprina Morrisii, Corbula longirostris, Scalaria Bowerbankii, &e. The greatest thickness of these beds is about 90 feet. FRENCH MIDDLE EOCENE FORMATIONS. GENERAL TABLE OF FRENCH EOCENE STRATA. A. UPPER EOCENE (Lower Miocene of many French authors.) English Equivalents. A. Calcaire de la Beauce, or upper fresh- water, see p. 184, and Grés de Fon- {septa serles, see p. 192. tainebleau, de. B. MIDDLE EOOENE. B, 1. Gypseous series and Middle fresh- water calcaire lacustre moyen. | Bembridge series, p. 194, B. 2. Caleaire siliceux, (in part contem- poraneous with the succeeding } Lower part of the Bembridge series. group ?) Osborne series, and upper and middle part of Headon series, Isle of Wight. Headon Hill sands, Barton, Upper Bagshot and part of Bracklesham beds. Bracklesham beds, B. 8. Grés de Beauchamp, or Sables Mo- yens. and Middle Caleaire Grossier. B. 5. Lower Caleaire Grossier or Glau- conie Grossiére. B. 4. Upper Calcaire Grossier oo Lower Bagshot. Intermediate in age B, 6. Soissonnais Sans or Lits coquilliers. between the Bracklesham beds and London Clay. C. LOWER EOCENE. Plastic clay and sand, with lignite o. Argile plastique et lignite. j (Woolwich and Reading series) The tertiary formations in the neighborhood of Paris consist of a series of marine and freshwater strata, alternating with each other, and filling up a depression in the chalk. The area which they occupy has been called the Paris basin, and is about 180 miles in its greatest length, from north to south, and about 90 miles in breadth, from east to west (see Map, p. 195). MM. Cuvier and Brongniart attempted, in 1810, to distinguish five different groups, comprising three freshwater Cx. XVI] MIDDLE AND LOWER EOCENE OF FRANCE. 223 and two marine, which were supposed to imply that the waters of the ocean, and of rivers and lakes, had been by turns admitted into and excluded from the same area. Investigations since made in the Hamp- shire and London basins haye rather tended to confirm these views, at least so far as to show, that since the commencement of the Eocene period there have been great movements of the bed of the sea, and of the adjoining lands, and that the superposition of deep sea to shallow water deposits (the London clay, for example, to the Woolwich beds) can only be explained by referring to such movements. Nevertheless, it appears, from the researches of M. Constant Prevost, that some of the alternations and intermixtures of freshwater and marine deposits, in the Paris basin, may be accounted for by imagining both to have been si- multaneously in progress, in the same bay of the same sea, or a gulf into which many rivers entered. To enlarge on the numerous subdivisions of the Parisian strata, would lead me beyond my present limits; I shall therefore give some examples only of the most important formations enumerated in the foregoing Table, p. 222. Beneath the Upper Eocene or “ Upper marine sands,” A, already spoken of (p. 194), we find, in the neighborhood of Paris, a series of white and green marls, with subordinate beds of gypsum, B. These are most largely developed in the central parts of the Paris basin, and, among other places, in the Hill of Montmartre, where its fossils were first studied by M. Cuvier. The gypsum quarried there for the manufacture of plaster of Paris occurs as a granular crystalline rock, and, together with the associated marls, contains land and fluviatile shells, together with the bones and skeletons of birds and quadrupeds. Several land plants are also met with, among which are fine specimens of the fan-palm or palmetto tribe (Flabellaria), The remains also of freshwater fish, and of crocodiles and other reptiles, occur in the gypsum. The skeletons of mammalia are usually isolated, often entire, the most delicate extremities being preserved ; as if the carcasses, clothed with their flesh and skin, had been floated down soon after death, and while they were still swoln by the gases generated by their first decomposition. The few accompany- ing shells are of those light kinds which frequently float on the surface of rivers, together with wood. M. Prevost has therefore suggested that a river may have swept away the bodies of animals, and the plants which lived on its borders, or in the lakes which it traversed, and may have carried them down into the centre of the gulf into which flowed the waters impregnated with sul- phate of lime. We know that the Fiume Salso in Sicily enters the sea so charged with various salts that the thirsty cattle refuse to drink of it. A stream of sulphureous water, as white as milk, descends into the sea from the volcanic mountain of Idienne on the east of Java; and a great body of hot water, charged with sulphuric acid, rushed down from the same volcano on one occasion, and inundated a large tract of country, 924 GYPSEOUS SERIES. [Cu. XVI. destroying, by its noxious properties, all the vegetation.* In like manner the Pusanibio, or “ Vinegar River,” of Colombia, which rises at the foot of Puracé, an extinct volcano, 7,500 feet above the level of the sea, is strongly impregnated with sulphuric and hydrochloric acids and with oxide of iron. We may easily suppose the waters of such streams to have properties noxious to marine animals, and in this manner the entire absence of marine remains in the ossiferous gypsum may be explained. There are no pebbles or coarse sand in the gypsum; a circumstance which agrees well with the hypothesis that these beds were precipitated from water holding sulphate of lime in solution, and floating the remains of different animals. In this formation the relics of about fifty species of quadrupeds, in- cluding the genera Paleotherium (see fig. 191), Anoplotherium (see fig, 190), and others, have been found, all extinct, and nearly four-fifths of them belonging to a division of the order Pachydermata, which is now represented by only four living species; namely, three tapirs and the daman of the Cape. With them a few carnivorous animals are associated, among which are the Hyenodon dasyuroides, and a species of dog, Canis Parisiensis, and a weasel, Cynodon Parisiensis. Of the Rodentia, are found a squirrel; of the Znsectivora, a bat; while the Marsupialia (an order now confined to America, Australia, and some contiguous islands) are represented by an opossum. Of birds, about ten species have been ascertained, the skeletons of some of which are entire. None of them are referable to existing species.f The same remark applies to the fish, according to MM. Cuvier and Agassiz, as also to the reptiles. Among the last are crocodiles and tor- toises of the genera Hmis and Trionyx. The tribe of land quadrupeds most abundant in this formation is such as now inhabits alluvial plas and marshes, and the banks of rivers and lakes, a class most exposed to suffer by river inundations. Among these were several species of Paleothere, a genus before alluded to (p. 210). These were associated with the Anoplotherium, a tribe intermediate be- tween pachyderms and ruminants. One of the three divisions of this family was called by Cuvier Xiphodon (see fig. 235). Their forms were slender and elegant, and one, named Xiphodon gracile (fig. 235), was about the size of the chamois; and Cuvier inferred from the skeleton that it was as light, graceful, and agile as the gazelle. When the French osteologist declared, in the early part of the present century, that all the fossil quadrupeds of the gypsum of Paris were ex- tinct, the announcement of so startling a fact, on such high authority, created a powerful sensation, and from that time a new impulse was given throughout Europe to the progress of geological investigation. Eminent naturalists, it is true, had long before maintained that the shells * Leyde Magaz. voor Wetensch Konst en Lett., partie v. cahier i p. 71. Cited by Rozet, Journ. de Géologie, tom. i. p. 48. { M. C. Prevost, Submersions Itératives, &c. Note 23. ¢ Cuvier, Oss. Foss., tom. iii. p. 255. Ca. XVI] CALCAIRE SILICEUX. 225 and zoophytes, met with in many ancient European rocks, had ceased to be inhabitants of the earth, but the majority even of the educated classes Fig. 235, Xiphodon gracile, or Anoplotheriwm gracile, Cuvier. Restored outline, continued to believe that the species of animals and plants now contem- porary with man, were the same as those which had been called into being when the planet itself was created. It was easy to throw discredit upon the new doctrine by asking whether corals, shells, and other crea- tures previously unknown, were not annually discovered? and whether living forms corresponding with the fossils might not yet be dredged up from seas hitherto unexamined? But from the era of the publication of Cuvier’s Ossements Fossiles, and still more his popular Treatise called “A Theory of the Earth,” sounder views began to prevail, It was clearly demonstrated that most of the mammalia found in the gypsum of Mont- martre differed even generically from any now known to exist, and the extreme improbability that any of them, especially the larger ones, would ever be found surviving in continents yet unexplored, was made manifest. Moreover, the non-admixture of a single living species in the midst of so rich a fossil fauna was a striking proof that there had existed a state of the earth’s surface zoologically unconnected with the present state of things. Calcaire siliceux, or Travertin inferieur, B, 2—This compact siliceous limestone extends over a wide area. It resembles a precipitate from the waters of mineral springs, and is often traversed by small empty sinuous cavities. It is, for the most part, devoid of organic remains, but in some places contains freshwater and land species, and never any marine fossils. The siliceous limestone and the calcaire grossier usually occupy distinct parts of the Paris basin, the one attaining its fullest de- velopment in those places where the other is of slight thickness, They are described by some writers as alternating with each other towards the centre of the basin, as at Sergy and Osny; and M. Prevost con- cludes, that while to the north, where the Bay was probably open to the 15 226 CALCAIRE GROSSIER. [Ca. XVL sea, a marine limestone was formed, another deposit of freshwater origin was introduced to the southward, or at the head of the bay. It is sup ' posed that during the Eocene period, as now, the ocean was to the north, and the continent, where the great lakes existed, to the south. From that southern region we may suppose a body of freshwater to have descended, charged with carbonate of lime and silica, the water being perhaps in sufficient volume to freshen the upper end of the bay. / The gypsum, with its associated marl and limestone, is, as before stated, in greatest force towards the centre of the basin, where the calcaire gros- sier and ealcaire siliceux are less fully developed. Hence M. Prevost infers, that while those two principal deposits were gradually in progress, the one towards the north, and the other towards the south, a river de- scending from the east may have brought down the gypseous and marly sediment. Gres de Beauchamp or Sables moyens, B, 3—In some parts of the Paris basin, sands and marls, called the Gres de Beauchamp, or Sables moyens, divide the gypseous beds from the calcaire grossier proper. These sands, in which a small nummulite (JV. variolaria) is very abundant, con- tain more than 300 species of marine shells, many of them peculiar, but others common to the next division. Calcaire grossier, upper and middle, B. 4.—The upper division of this group consists in great part of beds of compact, fragile limestone, with some intercalated green marls, The shells in some parts are a mixture of Cerithium, Cyclostoma, and Corbula ; in others Limneus, Cerithium, Paludina, &c. In the latter, the bones of reptiles and mammalia, Paleo- therium and Lophiodon, have been found. The middle division, or cal- caire grossier proper, consists of a coarse limestone, often passing into sand. It contains the greater number of the fossil shells which character- ize the Paris basin. No less than 400 distinct species have been pro- cured from a single spot near Grignon, where they are imbedded in a calcareous sand, chiefly formed of comminuted shells, in which, neyer- theless, Setaalnet in a pertect state of preservation, both of marine, terrestrial, and freshwater species, are mingled together. Some of the marine shells may have lived on the spot; but the Cyclostoma and Zimneus must have been brought thither by rivers and currents, and the quantity of triturated shells implies considerable moyement in the waters. Nothing is more striking in this assemblage of fossil testacea than the great proportion of species referable to the. genus Cerithium (see p. 30, fig. 44). There occur no less than 137 species of this genus in the Paris ine sin, and almost all of them in the calcaire grossier. Most of the living Cerithia inhabit the sea near the mouths of rivers, where the waters are brackish; so that their abundance in the marine strata now under consideration is in harmony with the hypothesis, that the Paris basin formed a gulf into which several rivers flowed, the sediment of some ‘of which gave rise to the beds of clay and lignite before mentioned ; ‘while a distinct freshwater limestone, called caleaire siliceux, already Cx. XVI] EOCENE FORAMINIFERA. 99 described, was precipitated from the waters of others situated farther to the south. In some parts of the calcaire grossier round Paris, certain beds occur of a stone used in building, and called by the French geologists “ Miliolite limestone.” It is almost, entirely made up of millions of microscopic shells, of the size of minute grains of sand, which all belong to the class Foraminifera. Figures of some of these are given in the annexed wood- cut. As this miliolitic stone never occurs in the Faluns, or Miocene strata EOCENE FORAMINIFERA, 2 Calearina rarispina, Desh. Spirolina stenostoma, Desh. 6. Natural size. a, c, Bame magnified. B. Natural size. A, C, D. Same magnified, Fig. 238, Triloculina inflata, Desh. d. Natural size. a, c, d. Same magnified. Fig. 239. Me Mitt i f Clawuline eorrugata, Desh. @, Natural size. b, c. Same magnified. of Brittany and Tourame, it often furmshes the geologist with a useful criterion for distinguishing the detached Eocene and Miocene forma- tions, scattered over those and other adjoining provinces. The dis- covery of the remains of Paleotherium and other mammalia in some of the upper beds of the calcaire grossier shows that these land animals began to exist before the deposition of the overlying gypseous series had commenced. 228 LITS COQUILLIERS. [Cu. XVI Lower Caleaire grossier, or Glauconie grossiere, B. 5.—The lower part of the calcaire grossier, which often contains much green earth, is char- acterized at Auvers, near Pontoise, to the north of Paris, and still more in the environs of Compiegne, by the abundance of nummulites, con- sisting chiefly of WV. levigata, N. scabra, and NV. Lamarcki, which con- stitute a large proportion of some of the stony strata, though these same foraminifera are wanting in beds of similar age in the immediate environs of Paris. Soissonnais Sands or Lits coquilliers, B. 6—Below the preceding formation, shelly sands are seen, of considerable thickness, especially at Cuisse-Lamotte, near Compiegne, and other localities in the Soissonnais, about fifty miles N. E. of Paris, from which about 300 species of shells have been obtained, many of them common to the Calcaire grossier and the Bracklesham beds of England, and many peculiar. The Vummulites planulata is very abundant, and the most characteristic shell is the Nerita conoidea, Lam., a fossil which has a very wide geographical . Fig. 240. Nerita conoidea, Lam, Syn. VY. Schmidelliana, Chemnitz. range ; for, as M. D’Archiac remarks, it accompanies the nummulitic for- mation from Europe to India, having been found in Cutch, near the mouths of the Indus, associated with Wummulites scabra. No less than thirty-three shells of this group are said to be identical with shells of the London clay proper, yet, after visiting Cuisse-Lamotte and other localities of the “Sables inférieures” of Archiac, I agree with Mr. Prestwich, that the latter are probably newer than the London clay, and perhaps older than the Bracklesham beds of England. The London clay seems to be unrepresented in France, unless partially so, by these sands.* One of the shells of the sandy beds of the Soissonnais is adduced by M. Deshayes as Tig. 241. NINS Cardium poruloswm. Paris and London basins. * D’Archiac, Bulletin, tom. x. ; and Prestwich, Geol. Quart. Journ. 1847, p. 37% Cu. XVL] NUMMULITIC FORMATIONS. 229 an example of the changes which certain species underwent in the succes- sive stages of their existence. It seems that different varieties of the Cardium porulosum are characteristic of different formations. In the Soissonnais this shell acquires but a small volume, and has many pecu- liarities, which disappear in the lowest beds of the calcaire grossier. In these the shell attains its full size, with many distinctive characters, which are again modified in the uppermost beds of the calcaire grossier ; and these last modifications of form are preserved throughout the “ upper marine” (or Upper Eocene) series.* Argile plastique (C, Table, p. 222).—At the base of the tertiary system in France are extensive deposits of sands, with occasional beds of clay used for pottery, and called “argile plastique.” Fossil oysters (Ostrea bellovacina) abound in some places, and in others there is a mixture of fluviatile shells, such as Cyrena cuneiformis (fig. 233, p. 220), Melania inquinata (fig. 234), and others, frequently met with in beds occupying the same position in the valley of the Thames. Layers of lignite also accompany the inferior clays and sands. Immediately upon the chalk at the bottom of ali the tertiary strats in France there generally is a conglomerate or breccia of rolled and angular chalk-flints, cemented by siliceous sand. These beds appear to be of lit- toral origin, and imply the previous emergence of the chalk, and its waste by denudation. Whether the Thanet sands before mentioned (p. 221) are exactly rep- resented in the Paris basin, is still a matter of discussion. Wide extent of the nummulitic formation in Europe, Asia, &e— When I visited Belgium and French Flanders in 1851, with a view of com- paring the tertiary strata of those countries with the English series, I found that all the beds between the Upper Eocene or Limburg formations, and the Lower Eocene or London clay proper, might be conveniently divided into three sections, distinguished, among other paleontological characters, by three different species of nummulites, VV. variolaria in the upper beds, WV. levigata in the middle, and WV. planulata in the lower. After I had adopted this classification, I found, what I had overlooked or forgotten, that the superposition of these three species in the order here assigned to them, had been previously recognized in the North of France, in 1842, by Viscount D’Archiac. The same author, in the valuable monograph recently published by him,t has observed, that a somewhat similar distribution of these and other species in time, prevails very widely in the South of France and the Pyrenees, as well as in the Alps and Apennines, and in Istrea,—the lowest nummulitic beds being charac- terized by fewer and smaller species, the middle by a greater number and by those which individually attain the largest dimensions, and the upper- most beds again by small species. Tn the treatise alluded to, M. D’Archiac describes no less than fifty- two species of this genus, and considers that they are all of them char- * Coquilles caractéristiques des terrains, 1831. + Animaux foss, du groupe nummul, de l’Inde: Paris, 1853. 230 NUMMULITIC FORMATIONS IN EUROPE, ETC. [Cu. XVI. acteristic of those tertiary strata which I have called Middle Eocene. In very few instances at least do certain species diverge from this narrow limit, whether into incumbent or subjacent tertiary formations, it being rather doubtful whether more than one of them, Vummulites ontermedia, also a Middle Eocene fossil, ascends so high as the Miocene formation, or whether any of them descend to the level of the London clay. Certainly they have never been traced so low down as the marine beds, coeval with the Plastic clay or Lignite, in any country of which the geology has been well worked out. This conclusion is a very unexpected result of recent inquiry, since for many years it was a matter of controversy whether the nummulitic rocks of the Alps and Pyrenees ought not to be ‘regarded as cretaceous rather than Eocene. The late M. Alex. Brongniart first declared the specific identity of many shells of the marine strata near Paris, and those of the nummulitic formation of Switzerland, although he obtained these last from the summit of the Diablerets, one of the loftiest of the Swiss Alps, which rises more than 10,000 feet above the level of the sea. The numinulitic limestone of the Alps is often of great thickness, and is immediately covered by another series of strata of dark-colored slates, marls, and fucoidal sandstones, to the whole of which the provincial name of “flysch” has been given in parts of Switzerland. The researches of Sir Roderick Murchison in the Alps in 1847 have shown that all these tertiary strata enter into the disturbed and loftiest portions of the Alpme chain, to the upheaval of which they enable us therefore to assign a com- paratively modern date. The nummulitic formation, with its characteristic fossils, plays a far more conspicuous part than any other tertiary group in the solid framework of ‘the earth’s crust, whether in Europe, Asia, or Africa. It often attaims a thickness of many thousand feet, and extends from the Alps to the Car- pathians, and is in full force in the north of Africa, as, for example, in Algeria and Morocco. It has also been traced from Egypt, where it was largely quarried of old for the building of the Pyramids, into Asia Minor, and across Persia by Bagdad to the mouths of the Indus. It occurs not only in Cutch, but in the mountain ranges which separate Scinde from Persia, and which form the passes leading to Caboul ; and it has been followed still far- ther eastward into India, as far as eastern Bengal and the frontiers of Chima, a, External surface of one of the nummulites, of which longitudinal sections are seen in the limestone. b. Transverse section of same. Cx. XVI] EOCENE STRATA. 231 Dr. T. Thomson found nummulites at an elevation of no less than 16,500 feet above the level of the sea, in Western Thibet. One of the species, which I myself found very abundant on the flanks of the Pyrenees, in a compact crystalline marble Fig. 248, (fig. 242) is called by M. D’Archiac Mummulites pe Puschi. The same is also very common in rocks of the same age in the Carpathians. Another large species (see fig. 243), Mummulites exponens, J. Sow., occurs not only in the South of France, near Des but in Germany, Italy, Asia Minor, and in Cutch; also in the mountains of Sylhet, on the _wwmmulites exponens. frontiers of China Sow. Europe and India, In many of the distant countries above alluded to, in Cutch, for exam- ple, some of the same shells, such as Werita conoidea (tg. 240), accom- pany the Nummulites as in France. The opinion of many observers, that the nummulitic formation belongs partly to the cretaceous era, seems chiefly to have arisen from confound- ing an allied genus, Orbitoides, with the true Nummulite. ~ When we have once arrived at the conviction that the nummulitic for- mation occupies a middle place in the Eocene series, we are struck with the comparatively modern date to which some of the greatest revolutions in the physical geography of Europe, Asia, and Northern Africa must be referred. All the mountain chains, such as the Alps, Pyrenees, Carpa- thians, and Himalayas, into the composition of whose central and loftiest parts the nummulitic strata enter bodily, could have had no existence till after the Middle Eocene period. During that period the sea prevailed where these chains now rise, for nummulites and their accompanying tes- tacea were unquestionably inhabitants of salt water. Before these events, comprising the conversion of a wide area from a sea to a continent, Eng- land had been peopled, as I before pointed out (p. 219), by various quadrupeds, by herbivorous pachyderms, by insectivorous bats, by opos- sums and monkeys. Almost all the extinct volcanoes which preserve any remains of their original form, or from the craters of which lava streams can be traced, are more modern than the Eocene fauna now under consideration ; and besides these superficial monuments of the action of heat, Plutonic influ- ences have worked vast changes in the texture of rocks within the same period. Some members of the nummulitic and overlying tertiary strata called flysch have actually been converted in the Central Alps into erys- talline rocks, and transformed into marble, quartz-rock, mica-schist, and gneiss.* EOCENE STRATA IN THE UNITED STATES. In North America the Eocene formations occupy a large area bordering the Atlantic, which increases in breadth and importance as it is traced southwards from Delaware and Maryland to Georgia and * Murchison, Quart. Journ. of Geol. Soc. vol. v., and Lyell, vol. vi. 1850, Annie versary Address, 932, EOCENE STRATA IN UNITED STATES. [Cx. XVL Alabama. They also occur in Louisiana and other states both east and west of the valley of the Mississippi. At Claiborne in Alabama no less than 400 species of marine shells, with many echinoderms and teeth of fish, characterize one member of this system. Among the shells, the Cardita planicosta, before mentioned (fig. 216, p. 214), is in abundance ; and this fossil, and some others identical with European species, or very nearly allied to them, make it highly probable that the Claiborne beds agree in age with the central or Bracklesham group of England, and with the calcaire grossier of Paris.* Higher in the series is a remarkable calcareous rock, formerly called “the nummulite limestone,” from the great number of discoid bodies resembling nummulites which it contains, fossils now referred by A. d@Orbigny to the genus Orbitoides, which has been Jemonstrated by Dr. Carpenter to belong to the foraminifera.t That naturalist moreover is of opinion that the Orbitoides alluded to (O. Mantelli) is of the same species as one found in Cutch in the Middle Eocene or nummulitic forma- tion of India. The following section will enable the reader to understand the position of three subdivisions of the Eocene series, Nos. 1, 2, and 3, the relations of which I ascertained in Clarke County, between the rivers Alabama and Tombeckbee. Fig. 244. Bettis Hill. Clarke County. Claiborne. a ee ee a ed —— 1. Sand, marl, &c., with numerous fossils. 2. White or rotten limestone, with Zeuglodon. Eocene. 8. Orbitoidal, or so called nummulitic, limestone. 4. Overlying formation of sand and clay without fossils. Age unknown. The lowest set of strata, No. 1, having a thickness of more than 100 feet, comprise marly beds, in which the Ostrea selleformis occurs, a shell ranging from Alabama to Virginia, and being a representative form of the Ostrea flabellula of the Eocene group of Europe. In other beds of No. 1, two European shells, Cardita planicosta, before mentioned, and Solarium canaliculatum, are found, with a great many other species pe- culiar to America. Numerous corals, also, and the remains of placoid fish and of rays, occur, and the “swords,” as they are called, of sword fishes, all bearing a great generic likeness to those of the Eocene strata of England and France. No. 2 (fig. 244) is a white limestone, sometimes soft and argillaceous, * See paper by the author, Quart. Journ. Geol. Soe. vol. iv. p. 12; and Second Visit to the U.S. vol. ii. p. 59. ¢ Quart. Journ. Geol. Soe. vol. vi. p. 32. Cu. XVI] EOCENE STRATA IN UNITED STATES. 233 but in parts very compact and calcareous. It contains several peculiar corals, and a large Nautilus allied to WV. ziezac ; also in its upper bed a gigantic cetacean, called Zeuglodon by Owen.* Fig. 245. Fig. 246. Zeuglodon cetoides, Owen. Basilosaurus, Harlan. Fig. 245. Molar tooth, natural size. Fig. 246. Vertebra, reduced. The colossal bones of this cetacean are so plentiful in the interior of Clarke County as to be characteristic of the formation. The vertebral column of one skeleton found by Dr. Buckley at a spot visited by me, extended to the length of nearly 70 feet, and not far off part of another backbone nearly 50 feet long was dug up. I obtained evidence, during a short excursion, of so many localities of this fossil animal within a dis- tance of 10 miles, as to lead me to conclude that they must have belonged to at least forty distinct individuals. Prof. Owen first pointed out that this huge animal was not reptilian, since each tooth was furnished with double roots (see fig. 245), implanted in corresponding double sockets; and his opinion of the cetacean nature of the fossil was afterwards confirmed by Dr. Wyman and Dr. R. W. Gibbes. That it was an extinct mammal of the whale tribe has since been placed beyond all doubt by the discovery of the entire skull of an- other fossil species of the-same family, having the double occipital con- dyles only met with in mammals, and the convoluted tympanic bones which are characteristic of cetaceans. Near the junction of No. 2 and the incumbent limestone, No. 3, next to be mentioned, are strata characterized by the following shells: Spon- dylus dumosus (Plagiostoma dumosum, Morton,) Pecten Poulsoni, Pecten perplanus, and Ostrea cretacea. No. 8 (fig. 244) is a white limestone, for the most part made up of the Orbitoides of D’Orbigny before mentioned (p. 232), formerly supposed to be a nummulite, and called WV. Mantelli, mixed with a few lunulites, some small corals, and shells.t The origin, therefore, of this cream- colored soft stone, like that of our white chalk, which it much resembles, is, I believe, due to the decomposition of these foraminifera. The surface of the country where it prevails is sometimes marked by the absence of wood, * See Memoir by R. W. Gibbes, Journ, of Acad. Nat. Sci. Philad. vol. i, 1847. + Lyell, Quart. Journ. Geol. Soc. 1847, vol. iv. p. 15. 234 3 CRETACEOUS GROUPS. [Ca XVIL like our chalk downs, or is covered exclusively by the Juniperus Virgini- ana, as certain chalk districts in England by the yew-tree and juniper. Some of the shells of this limestone are common to the Claiborne beds, but many of them are peculiar. It will be seen in the section (fig. 244, p. 232) that the strata of Nos. 1, 2, 3 are, for the most part, overlaid by a dense formation of sand or clay without fossils. In some points of the bluff or cliff of the Alabama river, at Claiborne, the beds Nos. 1, 2 are exposed nearly from top to bottom, whereas at other points the newer formation, No. 4, occupies the face of nearly the whole cliff. The age of this overlying mass has not yet been determined, as it has hitherto proved destitute of organic remains. The burr-stone strata of the Southern States contain so many fossils agreeing with those of Claiborne, that it doubtless belongs to the same part of the Eocene group, though I was not fortunate enough to see the rela- tions of the two deposits in a continuous section. Mr. Tuomey considers it as the lower portion of the series. It may, perhaps, be a form of the Claiborne beds in places where lime was wanting, and where silex, derived. from the decomposition of felspar, predominated. It consists chiefly of slaty clays, quartzose sands, and loam, of a brick-red color, with layers of chert or burr-stone, used in some places for mill-stones. CHAPTER XVI. CRETACEOUS GROUP. Lapse of time between the Cretaceous and Eocene periods—Whether certain formations in Belgium and France are of intermediate age—Pisolitic limestone —Divisions of the Cretaceous series in Northwestern Europe—Maestricht beds —Chalk of Faxoe—White chalk—Its geographical extent and origin—Formed in an open and deep sea—How far derived from shells and corals—Single pebbles in chalk—Chalk flints—Potstones of Horstead—Fossils of the Upper Cretaceous rocks—Echinoderms, Mollusca, Bryozoa, Sponges—Upper Green- sand and Gault—Chalk of South of Europe—Hippurite limestone—Cretaceous rocks of the United States. Havine treated in the preceding chapters of the tertiary strata, we have next to speak of the uppermost of the secondary groups, commonly called the chalk, or the cretaceous strata, from creta, the Latin name for that remarkable white earthy limestone, which constitutes an upper member of the group in these parts of Europe, where it was first studied. The marked discordance in the fossils of the tertiary, as compared with the cretaceous formations, has long induced many geologists to suspect that an indefinite series of ages elapsed between the respective periods of their origin. Measured, indeed, by such a standard, that is to say, by the amount of change in the Fauna and Flora of the earth effected in the interval, the time between the cretaceous and Eocene may have been as great as that Cu. XVIL] PISOLITIC LIMESTONE OF FRANCE. 235 between the Eocene and recent periods, to the history of which the last seven chapters have been devoted. Several fragmentary deposits have been met with here and there, in the course of the last half century, of an age intermediate between the white chalk and the plastic clays and sands, of the Paris and London districts, monuments which have the same kind of interest to a geologist, which certain medizval records excite when we study the history of nations. For both of them throw light on ages of darkness, preceded and followed by others of which the annals are com- paratively well known to us. But these newly discovered records do not fill up the wide gap, some of them being closely allied to the Eocene, and others to the eretaceous type, while none appear as yet to possess so dis- tinct and characteristic a fauna, as may entitle them to hold an indepen- dent place in the great chronological series. Among the formations alluded to, the Thanet Sands of Prestwich have been sufficiently described in the last chapter, and classed as Lower Eo- cene. To the same tertiary series belong the Belgian formations, called by Professor Dumont, Landenian and Heersian, although these are prob- ably of higher antiquity than the Thanet Sands. On the other hand, the Maestricht and Faxoe limestones are very closely connected with the chalk, to which also the Pisolitic limestone of France has been recently referred by high authorities. The Lower Landenian beds of Belgium consist of marls and sands, often -containing much green earth, called glauconite. They may be seen at Tournay, and at Angres, near Mons, and at Orp-le-Grand, Lincent, and Landen in the ancient province of Hesbaye, in Belgium, where they supply a durable building-stone, yet one so light as to be easily trans- ported. Some few shells of the genus Pholodamya, Scalaria, and others, agree specifically with fossils of the Thanet Sands; but most of them, such -as Astarte imcequilatera, Nyst, are peculiar. In the building-stone of Orp-le-Grand, I found a Cardiaster, a genus which, according to Professor E. Forbes, was previously unknown in rocks newer than the cretaceous. Still older than the Lower Landenian is the marl, or calcareous glav- conite of the village of Heers, near Waremme, in Belgium ; also seen at Marlinne in the same district, where I have examined it. It has been sometimes classed with the cretaceous series, although as yet it has yielded no forms of a decidedly cretaceous aspect, such as Ammonite, Baculite, Belemnite, Hippurite, &c. The species of shells are for the most part new; but it contains, according to M. Hébert, Pholodamya cuneata, an Kocene fossil, and he assigns it with confidence to the tertiary series. Pisolitic limestone of France-—Geologists have been still more at yariance respecting the chronological relations of this rock, which is met with in the neighborhood of Paris, and at places north, south, east, and west of that metropolis, as between Vertus and Laversines, Meudon and Montereau. It is usually in the form of a coarse yellow- ish or whitish limestone, and the total thickness of the series of beds, 236 CLASSIFICATION OF CRETACEOUS ROCKS. [Cs. XVIL already known is about 100 feet. Its geographical range, according tc M. Hébert, is not less than 45 leagues from east to west, and 35 from north to south. Within these limits it occurs in small patches only, rest- ing unconformably on the white chalk. It was originally regarded as cretaceous by M. E. de Beaumont, on the ground of its having undergone, like the white chalk, extensive denudation previous to the Eocene period ; but many able paleontologists, and among others MM. C. D’Orbigny, Deshayes, and D’Arehiac, disputed this conclusion, and, after enumerating 54 species of fossils, declared that their appearance was more tertiary than eretaceous. More recently, M. Hetert having found the Pecten quadri- costatus, a cretaceous species, in this same pisolitic rock, at Montereau near Paris, and some few other fossils common to the Maestricht chalk, and to the Baculite limestone of the Cotentin, in Normandy, classed it as an upper member of the cretaceous group, an opinion since adopted by M. Alcide D’Orbigny, who has carefully examined the fossils. The Nautilus Danicus (fig.249), and two or three other species found in this rock, are frequent in that of Faxoe in Denmark, but as yet no Ammonites, Hamites, Scaphites, Turrilites, Baculites, or Hippurites have been met with. The proportion of peculiar species, many of them of tertiary aspect, is confessedly large; and great aqueous erosion suffered by the white chalk, before the pisolitic limestone was found, affords an additional indi- cation of the two deposits being widely separated in time. The pisolitic formation, therefore, may eventually prove to be somewhat more inter- mediate in date between the secondary and tertiary epochs than the Maestricht rock. It should however be observed, that all the above-mentioned strata, from the Thanet sands to the Pisolitic limestone inclusive, and even the Maestricht rock, next to be described, exhibit marks of denudation experienced at various dates, subsequently to the consolidation ef the white chalk. This fact helps us in some degree to explain the remark- able break in the sequence of European rocks, between the secondary and tertiary eras, for many strata which once existed have doubtless been Swept away. CLASSIFICATION OF THE CRETACEOUS ROCKS. ; ‘The cretaceous group has generally been divided into an Upper and a Lower series, each of them comprising several subdivisions, distin- guished by peculiar fossils, and sometimes retaining a uniform mineral character throughout wide areas. The Upper series is often called famil- iarly the chalk, and the Lower the greensand, the last-mentioned name being derived from the green color imparted to certain strata by grains of chloritic matter. The following table comprises the names of the sub- divisions most commonly adopted : UPPER CRETACEOUS. A. 1. Maestricht beds and Faxoe limestones. 2. White chalk with flints. 8. Chalk marl, or gray chalk slightly argillaceous. Cz. XVIL] MAESTRICHT BEDS. 237 4, Upper greensand, occasionally with beds of chert, and with chloritic marl (craie chloritée of French authors) in the upper portion. 5. Gault, including the Blackdown beds. LOWER CRETACEOUS (or Neocomtan). B. 1. Lower greensand—Greensand, Ironsand, clay, and occasional beds of lime- stone (Kentish Rag). 2. Wealden beds or Weald clay and Hastings sands.* Maestricht Beds——On the banks of the Meuse, at Maestricht, reposing on ordinary white chalk with flints, we find an upper calcareous formation about 100 feet thick, the fossils of which are, on the whole, very peculiar, and all distinct from tertiary species. Some few are of species common to the inferior white chalk, among which may be mentioned Belemnites mucronatus (fig. 256, p. 245) and Pecten quadricostatus, a shell re- garded by many as a mere variety of P. quinquecostatus (see fig. 271). Besides the Belemnite there are other genera, such as Baculite and Ha- mite, never found in strata newer than the cretaceous, but frequently met with in these Maestricht beds. On the other hand, Voluta, Fasciolaria, and other genera of univalve shells, usually met with only in tertiary strata, occur. The upper part of the rock, about 20 feet thick, as seen in St. Peter’s Mount, in the suburbs of Maestricht, abounds in corals and Bryozoa, often detachable from the matrix; and these beds are succeeded by a soft yel- lowish limestone 50 feet thick, extensively quarried from time immemorial for building. The stone below is whiter, and contains occasional nodules of gray chert or chalcedony. M. Bosquet, with whom I examined this formation (August, 1850), pointed out to me a layer of chalk from 2,to 4 inches thick, containing green earth and numerous encrinital stems, which forms the line of de- marcation between the strata containing the fossils peculiar to Maestricht and the white chalk below. The latter is distinguished by regular layers of black flint in nodules, and by several shells, such as Terebratula carnea, (see fig. 267), wholly wanting in beds higher than the green band. Some of the organic remains, however, for which St. Peter’s Mount is cele- brated, occur both above and below that parting layer, and, among others, the great marine reptile called Mosasaurus (see fig. 247), a sau- rian supposed to have been 24 feet in length, of which the entire skull * M. Alcide D’Orbigny, in his valuable work entitled Paléontologie Francaise, has adopted new terms for the French subdivisions of the Cretaceous Series, which, so far as they can be made to tally with English equivalents, seem explicable thus. Etage Danien. Maestricht beds. Etage Senonien. White chalk, and chalk mari. Etage Turonien. _— Part of the chalk marl. _Etage Cenomanien. Upper greensand. Etage Albien. Gault. Etage Aptien. Upper part of lower greensand. Etage Neocomien. Lower part of same. Etage Neocomien inférieur. Wealden beds and contemporaneous marine strata. 238 CHALK OF FAXOE. [Ca. XVIL and a great part of the skeleton have been found. Such remains are chiefly met with in the soft freestone, the principal member of the Fig. 247, DMosasaurus eamperi. Original more than 8 feet long. Maestricht beds. Among the fossils common to the Maestricht and white chalk may be instanced the echinoderm (fig. 248). I saw proofs of the previous denudation of the white chalk exhibited in the lower bed of the Maestricht formation Fig. 248. in Belgium, about 30 miles 8. W. of Maestricht, at the village of Jendrain, where the base of the newer deposit consisted chiefly of a layer of well-rolled, black, chalk-flint pebbles, in the midst of which perfect specimens of T'hecidea radians and Belemnites mucronatus are im- bedded. ‘ Hemipneustes radiatus, Ag. Chalk of Faxoe.—In the island of Seeland, —_Spatangus radiatus, Lam. in Denmark, the newest member of the chalk eee OT te ae series, seen in the sea-cliffs at Stevensklint resting on white chalk with flints, is a yellow limestone, a portion of which, at Faxoe, where it is used as a building-stone, is composed of corals, even more conspicuously than is usually observed in recent coral reefs. It has been quarried to the depth of more than 40 feet, but its thickness is unknown. The im- bedded shells are chiefly casts, many of them of univalve mollusca, which are usually very rare in the white chalk of Europe. Thus, there are two species of Cyprea, one of Oliva, two of Mitra, four of the genus Cerithium, six of Fusus, two of Trochus, one Patella, one Hmarginula, &c.; on the whole, more than thirty univalves, spiral or patelliform. At the same time, some of the accompanying bivalve shells, echinoderms, and zoophytes are specifically identical with fossils of the true Cretaceous series. Among the cephalopoda of Faxoe may be mentioned Bacu- lites Faujasti and Belemnites mucronatus, shells of the white chalk. The Nautilus Danicus (see fig. 249) is characteristic of this formation ; and it also occurs in France in the calcaire pisolitique of Laversin (dept. of Oise). ; Cx. XVID] Sens. Fig, 250. Paris, London. Jerts, Valley of Bray. Hythe. Boulogne. Section from Hertfordshire, in England, to Sens, in France. WHITE CHALK. 939 Fig, 249, Nautilus Danicus, Schl.—Faxoe, Denmark, The claws and entire skull of a small crab, Brachyu- rus rugosus (Schlottheim), are scattered through the Faxoe stone, reminding us of similar crustaceans in- closed in the rocks of modern coral reefs. Some small portions of this coralline formation consist of white earthy chalk; it is therefore clear that this sub- stance must have been produced simultaneously; a fact of some importance, as bearing on the theory of the origin of white chalk; for the decomposition of such corals as we see at Faxoe is capable, we know, of forming white mud, undistinguishable from chalk, and which we may suppose to have been dispersed far and wide through the ocean, in which such reefs as that of Faxoe grew. White chalk (see Tab. p. 236, et seq.).—The highest beds of chalk in England and France consist of a pure, white, calcareous mass, usually too soft for a building- stone, but sometimes passing into a more solid state. It consists, almost purely, of carbonate of lime ; the strati- fication is often obscure, except where rendered distinct by interstratified layers of flint, a few inches thick, occa- sionally in continuous beds, but oftener in nodules, and recurring at intervals from 2 to 4 feet distant from each other. This upper chalk is usually succeeded, in the descend- ing order, by a great mass of white chalk without flints, below which comes the chalk marl, in which there is a slight admixture of argillaceous matter. The united thickness of the three divisions in the south of England equals, in some places, 1000 feet. The annexed section (fig. 250) will show the man- ner in which the white chalk extends from England into France, covered by the tertiary strata described in former chapters, and reposing on lower cretaceous beds, 240 ANIMAL ORIGIN OF WHITE CHALK. [Ca. XVIL Geographical extent and origin of the White Chalk.—The area over which the white chalk preserves a nearly homogeneous aspect is so vast, that the earlier geologists despaired of discovering any analogous de- posits of recent date. Pure chalk, of nearly uniform aspect and compo- sition, is met with in a northwest and southeast direction, from the north of Ireland to the Crimea, a distance of about 1140 geographical miles, and in an opposite direction it extends from the south of Sweden to the south of Bourdeaux, a distance of about 840 geographical miles. In Southern Russia, according to Sir R. Murchison, it is sometimes 600 feet thick, and retains the same mineral character as in France and, England, with the same fossils, including Lnoceramus Cuviert, Belemnites mucro- natus, and Ostrea vesicularis. But it would be an error to imagine that the chalk was ever spread out continuously over the whole of the space comprised within these limits, although it prevailed in greater or less thickness over large portions of that area. On turning to those regions of the Pacific where coral reefs abound, we find some archipelagoes of lagoon islands, such as that of the Dangerous Archipelago, for instance, and that of Radack, with sey- eral adjoining groups, which are from 1100 to 1200 miles in length, and 300 or 400 miles broad; and the space to which Flinders proposed to give the name of the Coralline Sea is still larger; for it is bounded on the east by the Australian barrier—all formed of coral rock,—on the west by New Caledonia, and on the north by the reefs of Louisiade. Although the islands in these areas may be thinly sown, the mud of the decomposing zoophytes may be scattered far and wide by oceanie currents. That this mud would resemble chalk I have already hinted when speaking of the Faxoe limestone, p. 288, and it was also remarked in an early part of this volume, that even some of that chalk, which appears to an ordinary observer quite destitute of organic remains, is nevertheless, when seen under the microscope, full of fragments of corals, bryozoa, and sponges; together with the valves of entomo- straca, the shells of foraminifera, and still more minute infusoria. (See p. 26.) Now it had been often suspected, before these discoveries, that white chalk might be of animal origin, even where every trace of organic struc- ture has vanished. This bold idea was partly founded on the fact, that the chalk consisted of carbonate of lime, such as would result from the decomposition of testacea, echini, and corals; and partly on the passage observable between these fossils when half decomposed and chalk. But this conjecture seemed to many naturalists quite vague and visionary, until its probability was strengthened by new evidence brought to light by modern geologists. We learn from Capt. Nelson, that, in the Bermuda Islands, and in the Bahamas, there are many basins or lagoons almost surrounded and inclosed by reefs of coral. At the bottom of these lagoons a soft white calcareous mud is formed, not merely from the comminution of corallines (or calcareous plants) and corals, together with the exuvize of foraminifera, Cz. XVIL] ANIMAL ORIGIN OF WHITE CHALK. 241 mollusks, echinoderms, and crustaceans, but also, as Mr. Darwin observed upon studying the coral islands of the Pacific, from the fecal matter ejected by echinoderms, conchs, and coral-eating fish. In the West Indian seas, the conch (Strombus gigas) adds largely to the chalky mud by means of its feecal pellets, composed of minute grains of soft calca- reous matter, exhibiting some organic tissue. Mr. Darwin describes gregarious fishes of the genus Scarws, seen through the clear waters of the coral regions of the Pacific browsing quietly in great numbers on living corals, like grazing herds of graminivor- ous quadrupeds. On opening their bodies, their Fig. 251. intestines were found to be filled with impure § chalk. This circumstance is the more in point, when we recollect how the fossilist was formerly puzzled by meeting, in chalk, with certain bodies, called “larch-cones,” which were afterwards rec- ognized by Dr. Buckland to be the excrement of fish. Such spiral coprolites (fig. 251), like the é scales and bones of fossil fish in the chalk, are ORE elo eget sete composed chiefly of phosphate of lime. In the Bahamas, the angel-fish, and the unicorn or trumpet-fish, and many others, feed on shell-fish, or on corals. The mud derived from the sources above mentioned may be actually seen in the Maldiva Atolls to be washed out of the lagoons through nar- row openings leading from the lagoon to the ocean, and the waters of the sea are discolored by it for some distance. When dried, this mud is very like common chalk, and might probably be made by a moderate pressure to resemble it more closely.* Mr. Dana, when describing the elevated coral reef of Oahu, in the Sandwich Islands, says that some varieties of the rock consist of aggre- gated shells, imbedded in a compact calcareous base as firm in texture as any secondary limestone; while others are like chalk, having its color, its earthy fracture, its soft homogeneous texture, and being an equally good writing material. The same author describes, in many growing coral reefs, a similar formation of modern chalk, undistinguishable from the ancient.+ The extension, over a wide submarine area, of the calcareous matrix of the chalk, as well as of the imbedded fossils, would take place more readily in consequence of the low specific gravity of the shells of mollusca and zoophytes, when compared with ordinary sand and mineral matter. ‘The mud also derived from their decomposition would be much lighter than argillaceous and inorganic mud, and very easily transported by currents, especially in salt water. Single pebbles in chalk.—The general absence of sand and pebbles in: the white chalk has been already mentioned; but the occurrence here and there, in the southeast of England, of a few isolated pebbles of * See Nelson, Geol. Trans, 1831, vol. vy. p. 108; and Geol. Quart. Journ. 1853, p- 200, + Geol of U. 5. Exploring Exped. p. 252, 1849. 16 242 PEBBLES IN CHALK. [Cu XVIL quartz and green schist, some of them 2 or 3 inches in diameter, hag justly excited much wonder. If these had been carried to the spots where we now find them by waves or currents from the lands once bordering the cretaceous sea, how happened it that no sand or mud was transported thither at the same time? We cannot conceive such rounded stones to have been drifted like erratic blocks by ice (see ch. x. and xi.), for that would imply a cold climate in the Cretaceous period ; a supposition inconsistent with the luxuriant. growth of large chambered univalyes, numerous corals, and many fish, and other fossils of tropical forms. Now in Keeling Island, one of those detached masses of coral which rise up in the wide Pacific, Captain Ross found a single fragment of green- stone, where every other particle of matter was calcareous ; and Mr. Dar- win concludes that it must have come there entangled in the roots of a large tree. He reminds us that Chamisso, the distinguished naturalist who accompanied Kotzebue, affirms, that the inhabitants of the Radack archipelago, a group of lagoon islands in the midst of the Pacific, ob- tained stones for sharpening their instruments by searching the roots of trees which are cast up on the beach.* It may perhaps be objected, that a similar mode of transport. cannot have happened in the cretaceous sea, because fossil wood is very rare in the chalk. Nevertheless wood is sometimes met with, and in the same parts of the chalk where the pebbles are found, both in soft stone and in a silicified state in flints. In these cases it has often every appearance of having been floated from a distance, being usually perforated by boring- shells, such as the Zeredo and Fistulana+ The only other mode of transport which suggests itself is sea-weed. Dr. Beck informs me that in the Lym-Fiord, in Jutland, the Fucus vesiculosus, often called kelp, sometimes grows to the height of 10 feet, and the branches rising from a single root form a cluster several feet in diameter. When the bladders are distended, the plant becomes so buoy- ant as to float up loose stones several inches in diameter, and these are often thrown by the waves high up on the beach. The Fucus giganteus of Solander, so common in Terra del Fuego, is said by Captain Cook to attain the length of 360 feet, although the stem is not much thicker than a man’s thumb. It is often met with floating at sea, with shells attached, several hundred miles from the spots where it grew. Some of these plants, says Mr. Darwin, were found adhering to large loose stones in the inland channels of Terra del Fuego, during the voyage of the Beagle in 1834; and that so firmly, that the stones were drawn up from the bottom into the boat, although so heavy that they could scarcely be lifted in by one person. Some fossil sea-weeds have been found in the Cretaceous formation, but none, as yet, of large size. But we must not imagine that because pebbles are so rare in the white * Darwin, p. 549. Kotzebue’s First Voyage, vol. iii p. 155. { Martell, Geol. of S. E. of England, p. 96. — Cu. XVIL] CHALK FLINTS. 243 chalk of England and France there are no proofs of sand, shingle, and clay having been accumulated contemporaneously even in European seas. The siliceous sandstone, called “ upper quader” by the Germans, overlies white argillaceous chalk or “ planer-kalk,” a deposit resembling in com- position and organic remains the chalk marl of the English series. This sandstone contains as many fossil shells common to our white chalk as could be expected in a sea-bottom formed of such different materials. It sometimes attains a thickness of 600 feet, and by its jointed structure and vertical precipices, plays a conspicuous part in the picturesque scenery of Saxon Switzerland, near Dresden. Chalk Flints—The origin of the layers of flint, whether in continuous sheets or in the form of nodules, is more difficult to explain than is that of the white chalk. No such siliceous masses are as yet known to ac- company the aggregation of chalky mud in modern coral reefs. The flint abounds mostly in the uppermost chalk, and becomes more rare or is entirely wanting as we descend; but this rule does not hold universally throughout Europe. Some portion of the flint may have been derived from the decomposition of sponges and other zoophytes provided with siliceous skeletons ; for it is a fact, that siliceous spicule, or the minute bones of sponges, are often met with in flinty nodules, and may have served at least as points of attraction to some of the siliceous matter when it was in the act of separating from chalky mud during the process of solidification. But there are other copious sources before alluded to, whence the waters of the ocean derive a constant supply of silex in solu- tion, such as the decomposition of felspathic rock (see p. 42), also min- eral springs rising up in the bed of the sea, especially those of a high temperature ; since their waters, if chilled when first mingling with the sea, would readily precipitate siliceous matter (see above, p. 42). Never- theless, the occurrence in the white chalk of beds of nodular or tabular flint at so many distinct levels, implies a periodical action throughout wide oceanic areas not easily accounted for. It seems as if there had been time for each successive accumulation of calcareo-siliceous mud to become partially consolidated, and for a rearrangement of its particles to take place (the heavier silex sinking to the bottom) before the next stratum was superimposed ; a process formerly suggested by Dr. Buck- Jand.* A more difficult enigma is presented by the occurrence of certain huge flints, or potstones as they are called in Norfolk, occurring singly, or arranged in nearly continuous columns at right angles to the ordinary and horizontal layers of small flints. I visited, in the year 1825, an extensive range of quarries then open on the river Bure, near Horstead, about six miles from Norwich, which afforded a continuous section, a quarter of a mile in length, of white chalk, exposed to the depth of 26 feet, and covered by a thick bed of gravel. The potstones, many of them pear-shaped, were usually about three feet in height, and one foot in their * Geol. Trans., First series, vol, iy. p. 413. 244 POTSTONES AT HORSTEAD. [Cu. XVIL transverse diameter, placed in vertical rows, like pillars at irregular dis- tances from each other, but usually from 20 to 30 feet apart, though some Fig, 252. Ups) i} i; From a drawing by Mrs. Gunn. View of a chalk pit at Horstead, near Norwich, showing the position of the potstones. times nearer together, as in the above sketch. These rows did not ter- minate downwards, in any instance which I could examine, nor upwards, except at the point where they were cut off abruptly by the bed of gravel. On breaking open the potstones, I found an internal cylindrical nucleus of pure'chalk, much harder than the ordinary surrounding chalk, and not crumbling to pieces like it, when exposed to the winter’s frost. At the distance of half a mile, the vertical piles of potstones were much farther apart from each other. Dr. Buckland has described very similar phenomena as characterizing the white chalk on the north coast of An- trim, in Ireland.* FOSSILS OF THE UPPER CRETACEOUS ROCKS. Among the fossils of the white chalk, echinoderms are very numerous; Fig. 253. Ananchytes ovatus: White chalk, upper and lower. a, Side view. bd. Bottom of the shell on which both the oral and anal apertures are placed ; the anal being more round, and at the smaller end. * Geol. Trans, First series, vol. iv. p. 413, “On Paramoudra,” &c. Cz. XVII] FOSSILS OF UPPER CRETACEOUS ROCKS. 945 and some of the genera, like Ananchytes (see fig. 258), are exclusively eretaceous. Among the Crinoidea, the Marsupite (fig. 260) is a charac- Micraster cor-anguinum. Galerites albogalerus, Lam, White chalk, White chalk. teristic genus. Among the mollusca, the cephalopeda, or chambered univalves, of the genera Ammonite, Scaphite, Belemnite (fig. 256), Bacu- lite (257-259), and Turrilite (262, 263), with other allied forms, present a great contrast to the testacea of the same class in the tertiary and recent periods. a. Belemnites mucronatus. 6. Same, showing internal structure. Maestricht, Faxoe, and white chalk. SSN a ae aw ae sense a= == -- RESESEED = Baculites anceps. Upper greensand, or chloritic marl, craie chloritée. France. A. D’Orb. Terr, Cret. Portion of Baculites Faujasit. _ Portion of Baculites anceps. Maestricht and Faxoe beds and white chalk. Maestricht and Faxoe beds and white chalk. Fig. 260. Fig. 261. YNarsupites Milleri. Scaphites equalis. Chloritio White chalk, marl of Upper Greensand, Dorsetshire, 246 FOSSILS OF UPPER CRETACEOUS ROCKS. ([Cs. XVIL Fig. 263. a. Fragment of Turrilites costatus. Chalk marl. Turrilites costatus. 6. Same, showing the indented border Chalk. of the partition of the chambers, Among the brachiopoda in the white chalk, the Terebratule are very abundant. These shells are known to live at the bottom of the sea, where Fig. 266. Terebratula Defrancit. Terebratula Terebratula pumilus. Terebratula Upper white chalk. octoplicata, (Magas pumitlus, Sow.) carnea. (Var. of 7. plicatilis.) Upper white chalk. Upper white chalk. Upper white chalk. the water is tranquil and of some depth (see figs. 264, 265, 266, 267, 268). With these are associated some forms of oyster (see figs. 275, 276, 277), and other bivalves (figs. 269, 270, 271, 272, 273). Fig. 269. TINS | Hh i\\ Terebratula biplicata, Crania Parisiensis, Pecten Beaweri, reduced to Sow. Upper cretaceous. inferior or attached one-third diameter. valve. Lower white chalk and chalk Upper white chalk. marl, Maidstone: Among the bivalve mollusca, no form marks the eretaceous era in Europe, America, and India in a more striking manner than the extinct genus Inoceramus (Catillus of Lam.; see fig. 274), the shells Cx. XVIL] FOSSILS OF UPPER CRETACEOUS ROCKS. 247 of which are distinguished by a fibrous texture, and are often met with in fragments, having probably been extremely friable. Pecten 5-costatus. Plagiostoma Hoperi, Sow. Plagiostoma spinosum, Sow. White chalk, upper and _ Syn. Lima Hoperi, Syn. Spondylus spinosus, lower greensands. White chalk and upper Upper white chalk. greensand. 1 Of the singular family called Rudistes, by Lamarck, hereafter to be mentioned as extremely characteristic of the chalk of Southern Europe, a Fig. 274. Fig. 275. 400080000 a20Gn00000m Inoceramus Lamarckii. Ostrea vesicularis.” Syn. Gryphea globosa. Syn. Catillus Lamarckii. Upper chalk and upper greensand. White chalk @iows rie Sussex, Tab, 28, g. 29). single representative only (fig. 278) has been discovered in the white chalk of England. Dstrea columba. Ostrea carinata. Chalk marl, upper and Syn. Gryphaa columba. lower greensand, Upper greensand, 248 MOLLUSCA, BRYOZOA, SPONGES. [Ca. XVI Fig. 279, Fig. 280. LEY : Foy Ga Boauaumneey/ Mortoni, Mantell. Houghton, Sussex. White chalk. Diameter one-seventh nat. size. : Fig. 278. Two individuals deprived of their upper valves, adhering together. 279. Same seen from above. 280. Transverse section of part of the wall of the shell, magnified to show the sucture, 281. Vertical section of the same. On the side where the shell is thinnest, there is one external furrow and corresponding internal tidge, a, 0, figs. 278, 279; but they are usually less prominent than in these figures. This species was first referred by Mantell to Hippurites, afterwards to the genus Radiolites. I have never seen the upper valve. The specimen above figured was discovered by the late Mr. Dixon. With these mollusca are associated many Bryozoa, such as Hschara and Escharina (figs. 282, 283), which are alike marine, and, for the Eschara disticha. a, Natural size. b. Portion magnified. White chalk. Les! Yas Gs WTANS Ventriculites radiatus. Mantell. Syn. Ocellaria radiata, D’Orb. White chalk. Escharina oceani. a. Natural size. db. Part of the same magnified. White chalk. most part, indicative of a deep sea. These and other organic bodies, es- pecially sponges, such as Ventriculites (fig. 284) and Siphonia (fig. 286), Cx. XVIL] FOSSILS OF THE UPPER CRETACEOUS BEDS. 249 are dispersed indifferently through the soft chalk and hard flint, and some of the flinty nodules owe their irregular forms to inclosed sponges, such as fig. 285 a, where the hollows in the exterior are caused by the branches of a sponge, seen on breaking open the flint (fig. 285 6). Fig. 286. A branching sponge in a flint, from the white chalk. From the collection of Mr. Bowerbank, Siphonia pyri- formis. Chalk marl. The remains of fishes of the Upper Cretaceous formations consist chiefly of teeth of the shark family, of genera in part common to the oreo] Palatal tooth of Ptychodus decurrens, Lower white chalk. Maidstone. Cestracion Phillippi; recent. Port Jackson. Buckland, Bridgewater Treatise, pl. 27, d. tertiary, and partly distinct. To the latter belongs the genus Ptychodus (fig. 287), which is allied to the living Port Jackson Shark, Cestracion 250 UPPER GREENSAND. (Ca. XVII Phallippi, the anterior teeth of which (see fig. 288 a) are sharp and cut- ting, while the posterior or palatal teeth (0) are flat, and analogous to the fossil (fig. 287). But we meet with no bones of land animals, nor any terrestrial or fluviatile shells, nor any plants, except sea-weeds, and here and there a piece of drift wood. All the appearances concur in leading us to con- clude that the white chalk was the product of an open sea of considerable depth. The existence of turtles and oviparous saurians, and of a Pterodactyl or winged lizard, found in the white chalk of Maidstone, implies, no doubt, some neighboring land; but a few small islets in mid-ocean, like Ascen- sion, formerly so much frequented by migratory droves of turtle, might perhaps have afforded the required retreat where these creatures laid their eggs in the sand, or from which the flying species may have been blown out to sea. Of the vegetation of such islands we have scarcely any in- dication, but it consisted partly of cycadeous plants; for a fragment of one of these was found by Capt. Ibbetson in the chalk marl of the Isle of Wight, and is referred by A. Brongniart to Clathraria Lyellui, Mantell, a species common to the antecedent Wealden period. The Pterodactyl of the Kentish chalk, above alluded to, was of gigantic dimensions, measuring 16 feet 6 inches from tip to tip of its outstretched wings. Some of its elongated bones were at first mistaken by able anat- omists for those of birds; of which class no osseous remains seem as yet to have been derived from the chalk, or indeed from any secondary or primary formation, except perhaps the Wealden. Upper greensand (Table, p. 105, &c.)—The lower chalk without flints passes gradually downwards, in the south of England, into an argillaceous limestone, “ the chalk marl,” already alluded to, in which ammonites and other cephalopoda, so rare in the higher parts of the series, appear. This marly deposit passes in its turn into beds called the Upper Greensand, containing green particles of sand of a chloritic mineral. In parts of Surrey, calcareous matter is largely intermixed, forming a stone called Jirestone. In the cliffs of the southern coast of the Isle of Wight, this upper greensand is 100 feet thick, and contains bands of siliceous lime- stone and calcareous sandstone with nodules of chert. The Upper Greensand is regarded by Mr. Austen and Mr. D. Sharpe, as a littoral deposit of the Chalk Ocean, and, therefore, contemporane- ous with part of the chalk marl, and .even, perhaps, with some part of the white chalk. For as the land went on sinking, and the cretace- ous sea widened its area, white mud and chloritic sand were always forming somewhere, but the line of sea-shore was perpetually varying its position. Hence, though both sand and mud originated simultane- ously, the one near the land, the other far from it, the sands in every locality where a shore became submerged, might constitute the under- lying deposit. Gault—The lowest member of the upper Cretaceous group, usually about 100 feet thick in the S. E. of England, is provincially termed Ox. XVII] THE BLACKDOWN BEDS. 251 Gault. It consists of a dark blue marl, sometimes intermixed with green- sand. Many peculiar forms of cephalopoda, such as the Hamite (fig. 291) Fossils of the Upper Greensand. Fig. 289, Fig. 290. a. Terebratula lyra. Upper Greensand. Ammonites Rhotomagensis. 6. Same, seen in profile. rance. Upper Greensand. Hamites spiniger (Fitton); near Folkstone. Gault, and Scaphite, with other fossils, characterize this formation, which, small as is its thickness, can be traced by its organic remains to distant parts of Europe, as, for example, to the Alps. The Piakienn beds in Dorsetshire, celebrated for containing many species of fossils not found elsewhere, have been commonly referred to the Upper Greensand, which they resemble in mineral character; but Mr. Sharpe has suggested, and apparently with reason, that they are rather the equivalent of the Gault, and were probably formed on the shore of the sea, in the deeper parts of which the fine mud called Gault was de- posited. Several Blackdown species are common to the Lower cretaceous series, as, for example, Trigonia caudata, fig. 299. We learn from M. D’Archiac, that in France, at Mons, in the valley of the Loire, strata of greensand occur of the same age as the Blackdown beds, and containing many of the same fossils. They are also regarded as of littoral origin by M. D’Archiac.* ; The phosphate of lime, found near Farnham, in Surrey, in such abun- dance as to be used largely by the agriculturist for fertilizing soils, occurs exclusively, according to Mr. R. A. C. Austen, in the upper greensand and gault. It is doubtless of animal origin, and partly coprolitic, prob- ably derived from the excrement of fish. * Hist, des Progrés de la Géol., &e., vol. iv. p. 860, 1851. 2952 HIPPURITE LIMESTONE. [Cx. XVIL HIPPURITE LIMESTONE. Difference between the chalk of the north and south of Europe-—By the aid of the three tests of relative age, namely, superposition, mineral character, and fossils, the geologist has been enabled to refer to the samme Cretaceous period certain rocks in the north and south of Europe, which differ greatly, both in their fossil contents and in their mineral composition and structure. If we attempt to trace the cretaceous deposits from England and France to the countries bordering the Mediterranean, we perceive, in the first place, that the chalk and greensand in the neighborhood of London and Paris form’ one great continuous mass, the Straits of Dover being a trifling interruption, a mere valley with chalk cliffs on both sides. We then observe that the main body of the chalk which surrounds Paris stretches from Tours to near Poitiers (see the annexed map, fig. 292, in which the shaded part represents chalk). Between Poitiers and La Rochelle, the space marked A on the map separates two regions of chalk. This space is occupied by the Oolite and certain other formations older than the Chalk, and has been supposed by M. E. de Beaumont to have formed an island in the cretaceous sea. South of this space we again meet with a formation which we at once recognize by its mineral character to be chalk, although there are we some places where the rock becomes oolitic. The fossils are, upon the whole, very similar; especially certain species of the genera Spatangus, Ananchytes, Cida- rites, Nucula, Ostrea, Gryphea (Exogyra), Pecten, Plagiostoma (Lima), Trigonia, Catillus (Inoceramus), and Terebratula.* But Ammonites, as M. d’Archiac observes, of which so many species are met with in the chalk of the north of France, are scarcely ever found in the southern region; while the genera Hamite, Turrilite, and Scaphite, and perhaps Belemnite, are entirely wanting. On the other hand, certain forms are common in the south which are rare or wholly unknown in the north of France. Among these may be mentioned many Hippurites, Spherulites, and other members of that great family of mollusca called Rudistes by Lamarck, to which nothing analogous has been discovered in the living creation, but which 1s quite characteristic of rocks of the Cretaceous era in the south of Fig. 292. Y