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interesting lessons respecting the mode in which the Great Creator prepared this earth of ours to become the dwelling-place of man.

It will be seen, by taking a mere birds'eye-view of the panorama, that it consists of several distinct formations. Just as in some ivy-clad ruin we may often trace the work and style of many ages, -here a fragment of Roman masonry, there a characteristic arch of Saxon times,-on this side a zigzag moulding of the Norman age, and on that a graceful column of early English art; so, in the scene before us, we may discover many geological features perfectly distinct from each other in age and character. The valley, e.g., is covered with alluvium, gravel and peat; all of comparatively recent origin. The escarpments of the slopes on either side of the valley have generally a deposit of clay, overlying the chalk; the high ground on the north and south is covered with beds of gravel overlying the clay; which gravel, though often undistinguishable from that of the valley, is, as will presently be seen, of much greater age; and the chalk hills in the distance are of far higher antiquity still.

Let us go back in imagination to the time when those primæval hills emerged from their parent sea; and endeavour with such indications as the different strata furnish, to picture to ourselves some of the great geological changes which have occurred in this neighbourhood since that remote period. The present distribution of land and water, it need hardly be said, is the result of very recent causes. During the whole of the tertiary epoch, the physical geography of the globe was continually fluctuating; ancient continents gradually disappearing, and new islands rising and expanding above the waters. At the commencement of this period when the chalk area, after having been for ages dry land, was slowly subsiding to its old level beneath the sea, the waves swept into a depression of the great cretaceous continent, and in course of time formed a bed of light-coloured sand and greenish flints, which has been designated the Thanet sands, from the circumstance of their being well developed in the isle of Thanet. This formation is found chiefly in Kent and Essex, and extends only a few miles west of London. Its fossils, of which there are about forty species,

are all of marine forms; and during its deposition the land seems to have gone on subsiding and the sea encroaching; for the oceanbed, which immediately overlies it, has a much more extensive area stretching east and west from Berkshire to Suffolk and covering a large portion of Essex, Middlesex and Kent. The neighbourhood of Hungerford probably formed the western shore of that ancient sca, and the mass of black flint pebbles, which lie eight or ten feet in depth, about a mile south of Kintbury, occupy perhaps a portion of the coast line on which the surging waves were wont to beat. Then began the deposition of strata known to geologists as the "Woolwich and Reading series." Most of the bricks and tiles in the district of Newbury and Hungerford are made of clay and sand belonging to this formation. Between those towns it crops out abundantly along the hill slopes of the Kennet Valley, underlying the gravel on the north side between Speen and Wickham, and on the south from the river to the base of the chalk hills, where a narrow zone of it is exposed. At its junction with the chalk in many of the claypits, as at Speen and Shaw, e.g. a bed of oyster shells is found, very like, though distinct from existing species; and they are invariably perforated with small holes, the work no doubt of parasites, similar to those which drill our modern oyster shells. The mineral character of this formation is somewhat variable. Its lowest bed generally consists of sand and pebbles; and the remainder of clays, mottled red, blue, and brown, intercalated with layers of sand. Fossils are abundant in those beds at Woolwich and elsewhere; but in the district under notice very few exist besides the oyster shells above mentioned; and those which occur are in a very perished condition. They consist of sharks' teeth, bones of turtles, and a few small shells of marine origin. At Woolwich the formation yields fresh-water fossils in abundance; and vegetable remains are also common. At Reading, too, Mr. Prestwich discovered in the

The following have been found in the bottom- bed of this series at Shaw clay-pit:- Chelonia, bones of. Lamna, teeth of. Ostrea Bellovacina. Cardium. Tellina. Cythera Mulleri. Echinoderm, minute species of. Globulina. Memoirs of the Geological Survey, No. 12, p. 21.

railway cutting on the west side of the town, at the base of the mottled clay and a few feet above the chalk, hundreds of leaves of plants "impressed as finely as on wax and with every marking preserved." They are supposed to have belonged to trees resembling, though not identical with the fig, mulberry, walnut, and other plants which indicate a warm though not a tropical climate. These characteristics of the strata enable us to state many of the conditions under which they must have been formed; and to imagine how strangely different from its present aspect the face of nature around us must then have been. The materials of the rivers have very few affinities with the chalk, and seem to have been produced from the denudation of primary rocks. We therefore infer that they were brought hither by a sea turbid with the debris of mighty rivers, which swept down from remote hills even then crumbling with age, and now perchance buried beneath the waves. The intermingling of fresh water and marine deposits in many places, leads us to the conclusion that the coast must have been low and swampy; at one time enclosing lakes and lagoons behind its sandbanks, and at another inundated by the sea. The organic remains are of a very distinctive character, differing widely from those of the chalk beneath, and differing also, though in a less degree, from existing organisms. Geologists have appropriately designated this and the succeeding series eocene, or the dawn, because in them the forms of life which now flourish around us first begin to appear. About one fifth of the shells found in the Woolwich and Reading beds may be classed under existing genera, though in species none of them are identical with their modern analogues; but not a single specimen remains of the myriads of races which peopled land and sea during the chalk epoch.

Overlying those beds of clay and sand we find a layer of flint pebbles, perfectly rounded and extremely brittle, falling to pieces under a gentle blow of the hammer; and next, in ascending order come the great deposits of argillaceous strata known as the London Clay and Bagshot Sands. In many parts of the Kennet district, however, those beds have been entirely swept away by the floods

The Ground beneath us, p. 64.

which, long after their formation spread over the country the present superficial coating of gravel. But a considerable area of them still remains. On the south side of the Kennet they crop out in many places, and a good section of them may now be seen, in junction with the Woolwich and Reading beds, at Kintbury brickyard, north of Pebble Hill.

[graphic][merged small][merged small][merged small][merged small][merged small]

a. Tough ferruginous-brown clay.
At about 16 inches from the
bottom there are occasional flat-
tened concretionary nodules of
clay-iron-stone, about 3 inches
thick, under a layer of scattered
flint-pebbles (b), which are for
the most part small and white.
c. Ferruginous-brown sandy clay or
clayey sand, about 4 feet.
d. Black clay; very hard and homo-
geneous and splitting up when
dry very unevenly with a sort of
conchoidal fracture, about 3 feet.
e. A line of flint pebbles. At the
out crop this bed forms a con-
tinuous band of clay-ironstone 4
or 5 inches thick, with small
imbedded flints.
Greenish loamy clay passing down-
wards into more decided solid
clay at the depth of about 3 feet.

Fig. 1.-Junction of London Clay and Woolwich and Reading Beds at Kintbury Brickyard, North of Pebble Hill.

In places where these strata occur in their normal condition, as e.g. in the vicinity of London, they are from 380 to 480 feet in thickness, but in this district they have been much denuded. Westward from Reading they gradually thin off, and terminate in some shallow outliers near Great Bedwin. Fossils in great variety and abundance are generally found in the formation, although here they are comparatively rare. The places in which they occur most plentifully are the clay-pits at Kintbury, Shaw, and on Kingsclere Common. Besides shells, all of which differ from living species, those clay-pits have yielded fossil-wood, bones of turtles, sharks'

teeth, and vertebræ of fish. Where the formation is better exposed, as at Herne Bay and the Isle of Sheppey, organic remains have been discovered in such profusion and perfection, that we are enabled to describe the characteristics of the fauna and flora which flourished under those skies, when the clay was deposited. Let us endeavour in imagination to clothe those fossils with flesh and blood, and to picture to ourselves the strange scene which would have met our gaze if we could have stood for a few moments on the top of Inkpen beacon at that remote epoch.

We look down on the western shore of a wide sea, which stretches away eastward to the horizon, a sea deep as the Atlantic, and teeming with life-sharks, larger than any which now exist, prey upon myriads of creatures that people the waters-turtles, of which no less than ten species have been found, bask upon the sands. Here and there clusters of bright coral gem the haunts of innumerable crustacea, and graceful nautili adorn the placid bosom of the sea. Crocodiles, different from any now alive, but resembling those which infest the rivers of Borneo, slumber on the sand banks. Strange quadrupeds, not unlike the tapir of South America, gambol on the plains. Trees of palm and other fruits, like those which flourish in the spice islands of the tropics, clothe the hill slopes with beauty; whilst birds, which look like the ancestors of our vultures, stalk proudly along the sandy shore; and monkeys, with other animals of sunny climes, make the tangled vallies resound with their undisturbed merriment.

"Slides the bird o'er lustrous woodland, droops the trailer from the crag; Droops the heavy-blossom'd bower, hangs the heavy-fruited tree,-— Summer isles of Eden lying in dark-purple spheres of sea."

For countless ages the same plants and animals continued to flourish; and the ocean ceased not to ebb and flow at the base of those chalk hills. Some idea of the vast duration of the period may be formed from the fact first mentioned, that in certain places where the sediment which was then deposited remains undisturbed, it now lies in beds upwards of 400 feet in thickness. During the whole of this epoch there went on, it is supposed, a constant sinking of the land in this portion of the earth's crust; for in certain parts

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