At the conclusion of the Wealden period, the crust of our globe underwent another great change. The fresh-water rocks we have just been studying were probably submerged by some violent subterranean or subaquean agency, and upon a great part of them a new deposit was gradually formed. Foot by foot, and inch by inch, slowly accumulated those cretaceous particles (Lat. creta, chalk) which now constitute the chalk hills and cliffs of our own country, to say nothing of the extent of territory in Europe occupied by this well-known mineral. To those who like ourselves live in a chalk district, this formation possesses special interest, simply because the “bounds of our habitation” are fixed there; and though we miss here all traces of the Ichthyosaurus and Iguanodon, although no Deinotherium nor Mastodon as yet make their appearance on the stage of being, yet with a very little knowledge of geology, coupled with a desire not to walk through the world with “eyes and no eyes,” it is in our power to invest many an otherwise motiveless walk with pleasurable interest. A cutting in the hills may reveal some unthought-of geological curiosity; a heap of flints may disclose some “rich and rare” fossils; and even a walk over the Downs, those breezy “downs” or “heaths” of southern England, covered with their short herbage, and dotted with their browsing sheep—those downs that undulate in such well-known forms of beauty, may be fruitful of suggestions concerning their origin, character and antiquity, that may be of healthful power in the development of an intellectual life.

We live—that is, we aforesaid—not on a fresh-water deposit, like the people of Purbeck, Hastings, and so on, but upon an old marine deposit. The huge cliffs of chalk that gave the name of Albion, the “white isle,” to our country, with all these downs, which rest upon chalk, having a depth or thickness of often more than two thousand feet, were once formed at the bottom of pre-Adamite oceans; and in process of time, as the secondary period drew near to its destined close, and other and higher types of life were to make their appearance, were upheaved by Him, “whose hands thus formed the dry land,” to serve the future purposes and contribute to the comforts of the coming lord of all.

Of this Albion we may well be proud, as the home of religion, the birth-place of true freedom, and the sanctuary of the oppressed. With Coleridge we exclaim:—

If we were to tell the story of the Chalk formation, it would run something after this fashion:—Once upon a time—but what time we don’t know, for man’s records only go back a few thousand years; but long, long ages before there was a man to till the earth—all this chalk lay out of sight at the deep bottom of the old, old sea. The tall cliffs at Dover, which Shakspeare would hardly recognise now with their tunnels and railroads, the wavy downs of Sussex and Surrey, the chalk hills of Hampshire, all that piece of Wiltshire called Salisbury Plain, and this line of country stretching away north to bluff Flamborough Head, and running down south to Weymouth and the isle of Purbeck, taking up in its course a good part of Buckinghamshire, Bedfordshire, Cambridgeshire, and Norfolk,—all this immense district, averaging probably a thousand feet in thickness, lay quietly at the bottom of the sea. Yes! it wasn’t created just pat in a moment, and set up in these hills and valleys, any more than sand was created sand, but gradually, grain by grain, it accumulated, ages rolling by while thus the earth was a-preparing. These undulating downs knew then no boys pursuing on them their healthful and gymnastic games; no fair riders then crossed these pleasant turfy swards, inhaling life and vigour from the air of heaven; no evening promenades for men of business, recreating the overworked physical nature,—then diversified the scene: but instead thereof crumbling particles of older rocks covered the floor of the ocean with their dust, so making green sand, while the waste and débris of coral reefs, ground up and pulverized, poured in their lavish contributions, so making chalk; (?) while above this deposit thus forming, the ocean waves rolled to and fro, and in their rise and fall, their daily ebb and flow, sounded their eternal bass in the ear of old father Time, who certainly then had no human children. Had we been there we should have seen as tenants of the “vasty deep,” pectens, plagiostamas, hamites, belemnites, and other odd-looking crustaceans, roaming about at their own sweet will; some ganoid fishes that have now such hard names, that to write them would interfere with the strain of this description; while here and there we might have spied a veteran remnant of the oolite come down by strange chance into the chalk, a solitary pterodactyle, snapped at and pounced upon by an ugly mososaurus, a sea crocodile standing four feet high. These, and such as these, were the tenants of that ocean, which then rolled over our heaths and downs; and when at length their period of life and purpose of creation were answered, these too all perished, and the secondary formation ended its wondrous career. The old ocean still rolls on, unchanged, unaltered still; but what changes has it seen in these long distant epochs of which geology tries to tell the story!

No one can write the history of the Chalk formation, without remembering his indebtedness to the patient and laborious toil of Dr. Mantell in this department, from whose “Geological Excursions round the Isle of Wight,”^[104] we give the following extract. “The features of a chalk district are so well known, that a brief notice will render local details unnecessary. The rounded summits of the hills, covered with short verdant turf—the smooth undulated outline of the downs unbroken, save by the sepulchral mounds of the early inhabitants of the country—the coombes and furrows ramifying and extending into the deep valleys, which abruptly terminate at the base of the hills, and appear like dried-up channels of rivulets and streams, though free from all traces of alluvial débris, thus bearing the impress of physical operations, of which the agents that produced them have long since passed away—are phenomena familiar to every one who has travelled over the downs of the south-east of England, and are displayed in the chalk districts of the ‘beautiful isle.’ These features are restricted to the hilly districts of the white chalk, and have resulted from the peculiar nature of the sedimentary detritus,^[105] of which the strata comprised in the upper division of the Cretaceous system are composed: for in the lower groups, clays, marls, sands, and sandstones prevail; and where these deposits approach the surface, and form the subsoil, the country is broken and diversified, and the landscape presents a striking contrast with the down scenery, as may be observed in the picturesque district which flanks the escarpment of the chalk hills. It may, perhaps, be necessary to remind the unscientific reader, that these strata are but an insulated portion of an ancient sea-bottom, or in other words, a mass of consolidated sediments formed in the profound depths of the ocean, in a very remote period of the earth’s physical history. This detritus is made up of inorganic and organic materials. The former consist of the débris of the cliffs and shores which encompassed the ancient sea, of the spoils of islands and continents brought down into the ocean by fresh-water currents, and of chemical deposits thrown down from mineral solutions. The organic substances are the durable remains of animals and plants which lived and died in the ocean, and of fluviatile and terrestrial species that were transported from the land by rivers and their tributaries; the whole forming such an assemblage of sedimentary deposits as would probably be presented to observation, if a mass of the bed of the Atlantic ocean, 2,000 feet in thickness, were elevated above the waters, and became dry land.”

We have alluded to the undulating character of the downs, so “well known,” as Mantell says, that “local details are unnecessary.” How correct this is may be seen in the following drawing, which represents a portion of Royston Heath.

All over this heath is found the “Royston crow,” during the winter months. This fine bird migrates hither from Norway, to avoid its severe winters, and is scientifically known as the “Hooded-crow, corvus cornix.” On its first arrival, when it is in its best plumage, it is comparatively tame, allowing the sportsman to approach very near; but as the season advances, acquaintance with the gun makes it very knowing and shy. It associates freely with the other crows, but its nest has never yet been found in England. About March the hooded-crow wholly disappears. The head, throat, and wings are black; the back and breast a “clear smoke-grey.” Norman, the bird-stuffer of this town, has always several fine specimens on hand.

As, in the case of the Carboniferous system, we ventured to say to the reader that it was not all coal, so in the Cretaceous system, we would remind him that it is not all chalk; but without going minutely into the subdivisions which the chalk formation has received, because this unpretending elementary treatise does not profess to teach geology, but simply aims, as we have ventured again and again to repeat, to infuse into the mind a desire of acquaintance with the marvels and truths of this science, we will just indicate the leading divisions and nomenclature of this deposit. First, there is the green sand; that is, first, beginning at the bottom or lower part of the formation: this may be well seen and studied in the neighbourhood of Cambridge, where we have procured many of its characteristic fossils, including several vertebræ and teeth of the otodus, a fish allied to the shark family, such as are figured in the opposite diagram.

At Potton and Gamlingay in Bedfordshire, and in the neighbourhood, this green sand is highly ferruginous, and the roads and fields present that peculiarly dark-red colour which is first singular and then wearisome to the eye. In the case of the Potton beds, the red colour is caused by oxidization or rust of iron; in the neighbourhood of Cambridge, &c., where there is the green sand, this is owing to the influence of “chloritous silicate of iron.” Then we have the galt or gault, a local term of which we cannot trace the etymology. The gault, however, is not of great thickness, but is likely to be the most interesting department of the Chalk to the beginner, on account of the abundance and peculiar appearance of its fossils. A ramble under the cliffs at Folkstone,^[106] where the gault may be seen in perfection, will amply repay any one for toil, dirt, and a few slips and bruises. He will there find evidences of a prolific and prodigal bestowment of life in the innumerable fragments of organic remains every where observable; and if he be patient,—if he won’t go running on from spot to spot, saying, as some do, “Oh, there’s nothing here;” if he will just persevere in a minute examination of every spot where organic remains may be detected, he will not come away without his reward in ammonites, hamites, and other cephalopodous mollusks, and most of them with that peculiar nacreous or mother-of-pearl lustre upon them which renders the fossils of this period so beautiful and attractive. Only we caution the explorer not to buy of the so-called guides. At Dover and Folkstone the rogues have a knack of getting a lump of gault, and sticking into it one or two common pyrites, which are very abundant in the cliff, bits of shell, ammonites, &c.; they then offer this conglomerate for sale, all rounded and smooth, assuring you upon their “sacred honour,” the honour of men who always draw upon their imagination for their facts, that they would not ask so much for it, only on account of its excessive rarity. As good economists always avoid cheap houses, and go to the best shops, so let the young geologist always go to the best shop: let him go to the cliff with his hammer, and work for himself. We picture a few fossils from the gault, only regretting that it is out of the power of our artist to convey their lustrous colours, as well as their curious forms.

Then comes, lastly, the Chalk: that is, the white chalk, divided into lower and upper; the lower being harder and mostly without flints, and the upper characterised by layers and bands of flint, sometimes nodular, as in Cambridgeshire, and sometimes flat almost as a pancake, as in the neighbourhood of Woolwich.

Above are some of the most characteristic fossils of the Chalk. No. 1 is a pecten, or oyster, called the “five-ribbed,” or quinque costatus; No. 2 is the plagiostoma spinosa, so called on account of its spines, a shell found frequently in our chalk or lime-pits; No. 3 is the intermediate hamite (Lat. hamus, a hook), “hamites intermedius;” No. 4 is the spatangus cor-anguinum, a very common fossil echinus in the chalk; No. 5 is the ananchytes ovata, found frequently in the Brighton and Ramsgate cliffs; No. 6 is a scaphite (Gr. skaphē, a skiff or boat); and the last is our old friend the belemnite, who has survived so many of this earth’s changes, and now finds himself a contemporary of the cretaceous inhabitants of the globe.

In many respects, the Chalk presents us with remarkable anomalies: we have sand, the green sand, but unlike in colour and in texture the sand of the old and new red sandstone, where we find it compressed and hardened into solid and compact masses of stone; we have clay, argillaceous beds such as the gault, but it is not clay hard and pressed into slaty rocks, but soft and compressible; and we have carbonate of lime, the chalk constituting the calcareous beds of this formation; but where we have met with it before it has been hard and solid limestone, and marble, not pliable and soft as in the Cretaceous system; and yet apparently it is all the same material as we have found in the earlier stages of the earth’s crust—the washings, degradations, and deludations of older and harder rocks, along with the secretions and remains of organized animals that once peopled this ancient earth; thus affording us, on a large scale, another illustration of the economy observable in all the works of God.

Having spoken of the fossil fishes of the Chalk, we here give drawings of two procured from the neighbourhood of Lewes, the famous fossil fishing-ground of the late Dr. Mantell; and it is due to the name and memory of the Chalk historian and geologist, to inform the reader that Dr. M. was the first who succeeded, by skilful removal of the surrounding chalk, in procuring a perfect ichthyolite from the cretaceous formation of England. The British Museum is now enriched by Dr. Mantell’s collection of fossil fishes, that once so much excited the admiration of Agassiz, when he saw them at Brighton.

Here let us again advert to the Deluge theory, not because our own minds are not satisfied on the point, but because theology and science alike demand a true statement of the facts of the case. We believe, as we said in a previous chapter, in the plenary inspiration of nature, just as we believe that the Scriptures were given by inspiration of God; and we are quite sure that both books, if they are not misinterpreted, will declare the glory of God in one common speech, and elevate the mind of man, to whom they speak, up to a more adoring trust and a profounder reverence. With Dr. Hitchcock we say, “It seems to me that the child can easily understand the geological interpretation of the Bible and its reasons. Why, then, should it not be taught to children, that they may not be liable to distrust the whole Bible, when they come to the study of geology? I rejoice, however, that the fears and prejudices of the pious and the learned are so fast yielding to evidence; and I anticipate the period, when on this subject the child will learn the same thing in the Sabbath school and in the literary institution. Nay, I anticipate the time as not distant when the high antiquity of the globe will be regarded as no more opposed to the Bible, than the earth’s revolution round the sun, and on its axis. Soon shall the horizon, where geology and revelation meet, be cleared of every cloud, and present only an unbroken and magnificent circle of truth.”^[107] But to return; this Deluge theory refers all existing fossils to “Noah’s flood,”—to that violent diluvial action, the graphic account of which is in the book of Genesis. Now, it is impossible to believe this if we look at a fossil: look, for instance, at this terebratula, and observe how perfectly uninjured it is, frail as is its shelly covering; or at this plagiostoma spinosa, and mark how susceptible it is of injury, and yet that its brittle spines are all unbroken; or at this inoceramus or catillus, and observe its delicate flutings, still in exquisite preservation, without fracture or distortion; or these specimens of echinites, the ananchytes ovata, or the spatanguscor-anguinum, and see the markings on the shell, the apertures of the mouth and stomach still perfect; who can see all this and not come to the conclusion, that these creatures, and thousands such as these, endured not only no violence in death, such as a deluge would suppose, but that at death they subsided quietly to the bottom of the sea, there to find a fitting sepulchre of soft cretaceous matter prepared for them, which in process of time was lifted up, to exhibit in a hard chalky bed their forms of pristine beauty?

In the upper chalk every one has seen the layers of flint, and marked their singular distribution, in layers; and here we would add, that the existence of flint in chalk is one of those hard nuts which geology has not yet cracked. The geologist, the chemist, and the zoologist have all puzzled themselves in vain to find a truly satisfactory origin for these nodules of siliceous matter. We have heard it suggested that they may be coprolites; but no one who examines the texture of a flint, can hold that theory, to say nothing of the idea that the coprolites have been preserved, while the animal remains have perished. We may sum up all we have to say about flints in the following words, from that useful little book, Chambers’s “Rudiments of Geology:”

“The formation of flint, within a mass so different in composition as chalk, is still in some respects an unsolved problem in geology. It occurs in nodular masses of very irregular forms and variable magnitude; some of these not exceeding an inch, others more than a yard in circumference. Although thickly distributed in horizontal layers, they are never in contact with each other, each nodule being completely enveloped by the chalk. Externally, they are composed of a white cherty crust; internally, they are of a grey or black silex, and often contain cavities lined with chalcedony and crystallized quartz. When taken from the quarry they are brittle and full of moisture, but soon dry, and assume their well-known hard and refractory qualities. Flints, almost without exception, enclose remains of sponges, alcyonia, echinida, and other marine organisms, the structures of which are often preserved in the most delicate and beautiful manner. In some specimens the organism has undergone decomposition, and the space it occupied either left hollow, or partially filled with some sparry incrustation. From these facts, it would seem that flints are as much an aggregation of silex around some organized nucleus, as septaria are aggregations of clay and carbonate of iron. This is now the generally received opinion; and when it is remembered that the organisms must have been deposited when the chalk was in a pulpy state, there can be little difficulty in conceiving how the silex dissolved through the mass would, by chemical affinity, attach itself to the decaying organism. Chalk is composed of carbonate of lime, with traces of clay, silex, and oxide of iron; flint, on the other hand, consists of 98 per cent. of pure silex, with a trace of alumine, oxide of iron, and lime. Silex is quite capable of solution: it occurs in the hot-springs of Iceland and most thermal waters; has been found in a pulpy state within basalt; forms the tabasheer found in the cavities of the bamboo, and the thin pellicle or outer covering of canes, reeds, grasses, &c.; and siliceous concretions are common in the fruits and trees of the tropics. All these facts point to a very general diffusion of silex in a state of solution; and whatever may have caused its abundance in the waters during the deposition of the upper chalk, there can be little doubt respecting the mode in which it has been collected around the organic remains of these early seas.”

At Scratchell’s Bay in the Isle of Wight, it will be seen that the flints are in a vertical position; and to the most casual observer the perpendicular arrangement of these flints will supply the strongest evidence of disturbance by upheaval from below. The bay in front, called Scratchell’s Bay, is a small but romantic indentation in the coast of the south side of the island, in which are the famous Needles. In the face of the cliff is a noble archway between 200 and 300 feet high, which has been created by the constant action of water eating and wearing away the lower beds; while the Needles themselves are only isolated masses of chalk, separated or eroded from the main land by the same erosive action. “To the late Sir Henry Inglefield belongs the merit of having first observed and directed attention to the highly interesting phenomena of vertical chalk strata, occasioned by the disruption and elevation of the eocene and cretaceous formations, which are so remarkably displayed in the Isle of Wight, where the vertical position of the strata, and the shattered condition of the flint nodules, thought still embedded in the solid chalk, may be conveniently studied in the cliffs in the neighbourhood of Scratchell’s Bay.”^[108]

With the study of the Chalk formation, we close what has been appropriately termed the “secondary period, or middle epoch of the ancient world;” of which it has been well said, “In reviewing the characters of the Cretaceous group, we have evidence that these varied strata are the mineralized bed of an extensive ocean, which abounded in the usual forms of marine organic life, as algæ, sponges, corals, shells, crustacea, fishes, and reptiles. These forms are specifically distinct from those which are discovered in the tertiary strata; in many instances, the genus, in all the species, became extinct with the close of the Cretaceous period. It affords a striking illustration of creative power, that of the hundreds of species which composed the Fauna and the Flora of the Cretaceous group, not one species passed into the succeeding epoch.”^[109]

Of that old ocean with its countless tenants we have already spoken, and conclude by applying to it the well-known lines of Montgomery, in his celebration of the coral insect in his “Pelican Island:”—