➡the numerous remains of extinct species of land animals, dispersed through the superficial gravel all over the earth; phenomena to be examined in a subsequent chapter.

Other appearances in the strata have been referred to the denudating force of a mighty deluge. In the granites of the upper Vivarais we behold mountains seemingly torn asunder, immense mural precipices, terminated by acute angles, and enclosing between them the most frightful chasms. Mount Cer. vin an insulated pyramid more than 3000 feet high, placed on the loftiest ridge of the Alpine chain, is an eloquent witness of the great aqueous catastrophe. "However keen a partisan I am of crystallization," says Saussure, "it is impossible for me to believe that such an obelisk, issued directly from the hands of nature, in this form. The surrounding matter has been broken off and swept away; for nothing is to be seen around it, but other summits, springing like it, abruptly out of the ground, with their flanks in like manner, abraded by violence."

At Greiffenstein in Saxony in a gneiss district, separate columns, or rather thin granitic prisms are seen rising from the plain, more than a hundred feet high. These are divided by horizontal fissures or joints into successive courses, or we might say tables, so that each column seems built of great slabs of granite regularly piled over each other. Certainly no person, on viewing these pillars and the subjacent level ground, will believe that they were formed as they stand, either by crystallization in a menstruum, or shot up by igneous eruption, or left alone after subsidence of the plain. They are manifestly the

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remains of a great field of granite which once covered the whole space, like many other districts in the neighbourhood, but which was dislocated, ploughed up, and excavated at the universal deluge.

The mountains called moles, which rise insulated from the centre of extensive plains, seem also to be the diluvial debris of some great mineral districts of which they formed portions. The Landscrone may be adduced as a good example. It is a mountain placed in the middle of the plains of Lusace, about 2 leagues from the foot of the chain which bounds this country to the south, and presents the figure of a sugar loaf, nearly a thousand feet high, with the summit cut off. Like the territory, and the mountain chain in the neighbourhood, it consists of granite, capped over its whole top, with a platform of basalt, from 220 to 250 feet thick. This basalt is merely an insulated portion of the general coulee, that covers the granite district, about 2 leagues from it. It is hence obvious that the intermediate table land must have been swept away; for no one can possibly conceive of a basaltic lava effused on the top of an insulated cone of such elevation.

Mount Meissner in Hesse, six leagues south-east of Cassel, also deserves to be noticed here. It rises, colossus-like above the surrounding mountains, from which, however, it is completely insulated. Its summit forms a plain, 2 leagues long, and 1 league broad, at a height of more than 1900 feet above the river which flows at its base, and about 2200 feet above the level of the sea. The body of the mountain, in common with the country all around, consists of shell-limestone and sandstone.

Above these, on a stratum of sand, a bed of fossil wood reposes, one hundred feet thick in several places. This wooden floor is covered by a vast pavement or coulee of basalt, from 300 to 500 feet thick, which composes the upper platform. An observer who studies the composition of this interesting mountain and of the neighbouring districts, cannot help concluding that the enormous pile of wood, imbedded at such a height above the existing country, must have been drifted thither (for such a mass of trees could never have grown in one place), while the surface was yet continuous and depressed. The basalt must have been thereafter effused over them, obviously in a lava state. The explosive forces under the ocean bed which caused the deluge, first upheaved the general mountain masses, and the retiring deflux excavated the strata round Mount Meissner, leaving it an insulated mole, towering boldly above all the country, through an area of nearly 40 miles.

ocean.

The geognostic student sees in the organic remains of the secondary formations, described in Book Second, irresistible proofs that many strata of our present dry land, were deposited under the I conceive, moreover, that good evidence of the former submarine position of a large portion of the earth, is afforded by the saline impregnation of many of its extensive plains. Every traveller through the deserts of Africa and Arabia, describes the soil to be salt, and the water to be brackish, in almost every district. The subsoil is generally clay, which prevents the saline matter from being washed deep into the ground by the tropical rains.

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In the sands bordering on Egypt, the salt occurs often in balls and irregular lumps; and the great desert of Barbary is in some places covered with a saline crust, of such whiteness as to resemble statuary marble, and of such thickness as to be quarried into square blocks, for building houses. It is applied to the same purpose at Ormutz in Persia. Olivier states in his Persian Travels, that the great plains, or deserts of that country consist of an argillaceous soil impregnated with salt. "This substance," says he, "is so abundant in that country, that being washed down by the rains, saline pools are formed in winter over the low grounds, almost every lake is more or less brackish." The great plains or steppes of Siberia are formed of clay, and present analogous phenomena, especially northward of the Caspian Sea, where a multitude of lakes occur, some fresh, others rendered saline by the muriate or sulphate of soda. The lake of Indersk 20 leagues in circumference, has its bottom covered with a crust of salt, like a cake of ice, more than six inches thick, hard as stone, and perfectly white. The argillaceous soil of the great table land of Mexico was found by Humboldt to be quite impregnated with salt. The lake of Penon Blanco, that dries up every summer, forms the great mine of salt for Mexico; from which more than 15,000 tons are annually carried away.

CHAP. II-CAUSES OF GEOLOGICAL CATASTROPHE.

IN In the Newtonian Philosophy, no other causes of natural events can be admitted than what are known

to be really operative, and adequate to account for the phenomena. This inductive law prohibits the employment of hypothetical assumptions, whose existence we cannot prove, such as the attraction of a comet in deranging the axis of the earth, or deluging it, by lifting the waters from their ocean bed. Nor will modern discovery suffer the theorist to summon from the bowels of the earth an ideal abyss to serve his purposes; far less allow him to get rid of a meteoric deluge imported by an aqueous coma for the occasion. Thus wisely circumscribed, but by no means fettered, we shall have no difficulty in finding actual and potential forces, capable of explaining the principal appearances, incident to the great diluvial catastrophe, and its precursor inundations. Eruptive powers similar to those which raised the primordial land, acting under the bottom of the primeval ocean, rolled its waters over the ancient continents, many of which were broken down and sunk in the sea, whilst new territories were upheaved and laid bare. We shall endeavour to establish these propositions by an extensive induction of well established facts, illustrative of volcanic agency, and basaltic eruption.

§ I. VOLCANIC ACTION.

This power, though sufficiently terrific in many of its recorded forms, has now a very limited range in comparison with its ancient extent, even in postdiluvian periods. Thus the extinct volcanoes of the Rhine, Hungary, Auvergne, and Italy, indicate a far greater magnitude of eruptive fire, than any described in history. Those which are now seen