CHAPTER XII.

Geological Coloring of the Landscape.- Close Proximity in this Neigh borhood of the various Geologic Systems. - The Oolite; its Medicinal Springs; how formed. - Cheltenham. - Strathpeffer. The Saliferous System; its Organic Remains and Foot-prints. Record of Curious Passages in the History of the Earlier Reptiles. - Salt Deposits. Theory. The Abstraction of Salt from the Sea on a large Scale probably necessary to the continued Existence of its Denizens. - Lower New Red Sandstone. - Great Geologic Revolution. - Elevation of the Trap. Hills of Clent; Era of the Elevation. - Coal Measures; their three Forests in the Neighborhood of Wolverhampton. - Comparatively small Area of the Birmingham Coal-field. - Vast Coal-fields of the United States. Berkeley's Prophecy. - Old Red Sandstone. -Silurian

System. Blank.

LET us now raise from off the landscape another integument, - let us remove the boulder clays and gravels, as we formerly removed the vegetable mould, and lay the rock everywhere bare. There is no longer any lack of color in the prospect; it resembles, on the contrary, a map variously tinted by the geographer, to enable the eye to trace his several divisions, natural or arbitrary. The range of trap-hills which furnishes our peak of survey is of a deep olive-green; the New Red Sandstone that spreads out so widely around it, of a bright brick-red. There is a coal-field on either hand, the barren field of the Forest of Wyre, and the singularly productive field of Dudley; and they both are irregularly checkered black, yellow, and gray. Beyond the Wyre field lies an immense district of a deep chocolate-red tint, a huge development of the Old Red Sandstone. Still further beyond, we may discern in the distance a bluish-gray province of great extent, much broken

into hills, which consists of an at least equally huge development of the Silurian; while, rising over the red saliferous marls in an opposite direction, we may see a series of flat, low-lying rocks of the Oolitic system, passing from a pale neutral tint into a smoky brown and a light straw-yellow. In such close proximity are the geological systems in this part of the country, that the geologist who passes the night in Birmingham on the Lower New Red Sandstone, may go and take an early breakfast on the Silurian, the Old Red, the Carboniferous, the Salif erous, or the Oolitic systems, just as he inclines. Good sections, such as our northern sea-coasts furnish, are all that are wanting to render the locality one of the finest in the kingdom to the student of the stony science: but these he misses sadly; and he, alas! cannot deal with the stubborn integuments of the country in reality, as we are dealing with them so much at our ease in imagination, on one of the summits of the Clent Hills.

The integument that falls to be examined first in order, after the boulder drift and the gravels, is the Oolitic one; but it occupies merely a corner on the verge of the horizon, and need not engage us long. One remark regarding it, however, though rendered familiar to the geologic reader by the writings of Murchison and Mantell, I shall venture to repeat. We have seen how this central district of the kingdom has its storehouses of coal, iron, salt, lime, — liberal donations to the wants of the human animal, from the Carboniferous, Saliferous, and Silurian systems; and to these we must now add its inexhaustible deposits of medicine, contributions to the general stock by the Oolitic system. Along the course of the Lias, medicinal springs. abound; there is no other part of England where they rise so thickly, or of a quality that exerts a more powerful influence on the human frame. The mineral waters of Cheltenham, for instance, so celebrated for their virtues, are of the number; and

the way in which they are elaborated in such vast quantities seems to be simply as follows:- They all rise in the Lias, a formation abounding in sulphate of iron, lime, magnesia, lignite, and various bituminous matters; but they have their origin far beneath, in the saliferous marls of the Upper New Red, which the Lias overlies. In the inferior formation they are simply brine springs: but brine is a powerful solvent; passing through the Lias, it acts upon the sulphur and the iron; becomes, by means of the acid thus set free and incorporated with it, a more powerful solvent still; operates upon the lime, upon the magnesia, upon the various lignites and bitumens; and at length rises to the surface, a brine-digested extract of Liasic minerals. The several springs yield various analyses, according to the various rocks of the upper formation which they pass through, some containing more, some less lime, sulphur, iron, magnesia; but in all the dissolving menstruum is the same. And such, it would appear, is the mode in which Nature prepares her simples in this rich district, and keeps her medicine-chest ever full.

Let us trace the progress of a single pint of the water thus elaborated, from where it first alights on the spongy soil in a wintry shower, till where it sparkles in the glass in the pumproom at Cheltenham. It falls among the flat hills that sweep around the ancient city of Worcester, and straightway buries itself, all fresh and soft, in the folds of the Upper New Red Sandstone, where they incline gently to the east. It percolates, in its downward progress, along one of the unworkable seams of rock-salt that occur in the superior marls of the formation; and, as it pursues, furlong after furlong, its subterranean journey, savors more and more strongly of the company it keeps ; becomes in succession hard, brackish, saline, briny; and then many fathoms below the level at which it had entered, escapes

from the sa iferous stratum, tarough a transverse fissure, into an inferior Liasic bed. And here it trickles, for many hundred yards, through a pyritiferous shale, on which its biting salts act so powerfully, that it becomes strongly tinctured by the iron oxide, and acidulated by the sulphur. And now it forces its upward way through the minute crevices of a dolomitic limestone, which its salts and acids serve partially to decompose; so that to its salt, iron and sulphur, it now adds its lime and its magnesia. And now it flows through beds of organic remains, animal and vegetable, now through a stratum of belemnites, and now a layer of fish, - now beside a seam of lignite, and now along a vein of bitumen. Here it carries. along with it a dilute infusion of what had been once the muscular tissue of a crocodile, and here the strainings of the bones of an ichthyosaurus. And now it comes gushing to the light in an upper Liasic stratum, considerably higher in the geologic scale than the saliferous sandstones into which it had at first sunk, but considerably lower with reference to the existing levels. And now take it and drink it off at once, without pause or breathing space. It is not palatable, and it smells villanously; but never did apothecary mix up a more curiouslycompounded draught; and if it be not as salutary as it is elaborate, the faculty are sadly in error.

The underground history of the mineral springs of Great Britain would form an exceedingly curious chapter. I visited, a few weeks since, the springs at Strathpeffer, and explored, as carefully as rather imperfect sections and rather limited time. permitted, the geology of the valley. The lower hills that rise around it are composed of the great conglomerate base of the Old Red Sandstone system. The denudation of ages has swept every trace of the superior strata from their sides and summits; but in the sheltered trough of the valley at least one

of the overlying beds has escaped. We find laid at length along the hollow bottom, like a pancake in a platter, the lower ichthyolitic bed of the formation, so rich in other parts of the country in animal remains, but which exists in this locality as a gray brecciated rock, devoid of visible fossils, but so largely saturated with the organic matter into which they have been resolved, that, when struck by the hammer, the impalpable dust set loose affects very sensibly the organs of taste, and appeals scarce less strongly to those of smell than the swinestones of England. And it is through this saturated bed that the mineral waters take their course. Even the upper springs of the valley, as they pass over it, contract, in a sensible degree, its peculiar taste and odor. The dweller on the sea-coast is struck, on entering the pump-room, by the familiarity of the powerful smell which fills the place. It is that of a muddy sea-bottom when uncovered by the ebb. He finds that, whatever else may have changed within the rock since the times of the Lower Old Red Sandstone, the scent of the ancient ooze of this system is exactly what it ever was; and he drinks the water, convinced, if a geologist, that if man did not come early enough in the day to breakfast on the fish of the Old Red, Acanthodiens, Dipteriens, Coccostei, and Pterichthyes, — he has at least come quite in time enough to gulp down as medicine. an infusion of their juices and their bones.

We strip off the Liasic integument, "as ye peel the fig when its fruit is fresh;" and it is with the Upper New Red formation, on which the Lias rests, its saliferous marls and vast beds of rock-salt, that we have now to deal. There occurs among the superior strata of the formation a bed of variouslycolored sandstone, of little depth, but great horizontal extent, remarkable for containing, what in England at least is comparatively rare in the New Red, organic remains. We find it