for instance, rows of brick, travertine, and tufo, succeeded one another at equal intervals throughout, and with corresponding dimensions, assuredly you would conclude, that the different fragments had originally formed one continuous wall, and that the breaches interposed were the result of time or violence. Precisely the same line of reasoning must lead us to conclude, that the valleys, which have manifestly cut the hills in two, have been excavated in them, by some agency equal to the effects. Dr. Buckland has been particularly successful in the examination of this appearance, on the coast of Devon and Dorset, of which he has given illustrative plates. From these, as well as from his description, it appears that the entire coast is cut by valleys running towards the sea, dividing the strata of the hills, so that they tally one with another. On the sides of these valleys are accumulations of gravel, manifestly deposited on the slopes of the hills, and at the bottom of the gorge, by the excavating cause. This cannot have been any agent now in operation, for no river runs through many of them; and in the gravel thus deposited are found the remains of animals, such as would be destroyed by a sudden flood, in the present order of creation.* Similar examples might be brought from the essays of other geologists.

* "Reliquiæ," p. 247.-" Geolog. Trans." vol. i. p. 96.

To this class of proofs I may refer another singular appearance, which seems attributable to the washing away, by water, of the sides of mountains. I allude to those huge pinnacles of granite, or other hard rock, which seem to stand detached and insulated from the neighbouring mountains. Mount Cervin, in the Vivarais, presents a pyramid 3,000 feet high upon the loftiest Alps, and is thus commented on by Saussure" However keen a partizan I am of crystallization, it is impossible for me to believe that such an obelisk, issued directly, from nature's hand, in this shape. The surrounding matter has been broken off and swept away; for nothing is seen around it but other pinnacles, springing, like it, abruptly out of the ground, with their sides, in like manner, abraded by violence." At Greiffenstein, in Saxony, are a number of granitic prisms, standing upon a plain, and rising to the height of a hundred feet, and upwards. Each of these is again divided, by horizontal fissures, into so many blocks; and thus they present the idea of a great mass of granite, the connecting parts of which have been violently torn away.*

Another class of phenomena which gives the same results, may be justly comprehended in the term proposed by De la Beche, the erratic block

* Saussure, "Voyage dans les Alpes," to. iv. p. 414. Ure, "New System of Geology," Lond. 1829, p. 370.

group. Dr. Buckland had before proposed the distinction between alluvial and diluvial formations; understanding by the former, those deposits which tides, or rivers, or other existing causes, make in their ordinary action, and by the latter, those which seem due to the agency of a more powerful cause, than any now at work,-such as a vast and overwhelming inundation. The constituents of this class may be reduced to two; first, deposits of sand or gravel, where no water now acts, or could well have acted, in the present order of things; and secondly, those larger masses, varying from some inches in diameter, to the weight of many tons, technically denominated, boulder stones. These, when small, are generally intermixed with the gravel; but often they surprise us with their huge masses, standing insulated and alone, on the side of a mountain, so as to verify the beautiful description of the poet,

"As a huge stone is sometimes seen to lie
Couched on the bald top of an eminence,
Wonder to all who do the same espy,

By what means it could hither come, or whence;
So that it seems a thing endued with sense,
Like a sea-beast crawled forth, that on a shelf
Of rock or sand reposeth, there to sun itself.”—

WORDSWORth.

De la Beche has paid particular attention to the circumstances in which deposits of gravel occur, and shows them to be incompatible with the

* Page 181.

theory,—that actual causes have produced them. Thus, we often find that the strata have been broken into what is called a "fault," over which the transported gravel lies quiet and undisturbed, thus showing, that a different action deposited it there, from that which caused the fracture of the strata. In like manner, wherever it has been possible to examine the ground under these deposits, we find the rocks, however hard, scored in furrows, as if a vast current, bearing heavy masses along, had passed over its surface. Upon these facts he reasons thus:-" Our limits will not permit greater details, which would require the necessary maps; but it would go far to support the supposition, that masses of water had passed over the land. Confining our attention to one district, it should be observed, that the dislocations are far greater, and the faults, evidently produced at a single fracture, far more considerable, than we can conceive possible from modern earthquakes. It is not, therefore, unphilosophical to infer, that a greater force, causing vibrations and fractures of the rocks, would throw a greater body of water into more violent movement, and that the wave or waves, bursting upon the land, or acting upon the bottom, at comparatively small depths, would have an elevation and destructive sweeping power, proportioned to the disturbing force employed.

"The next question that will arise is, are there

any other marks of masses of water passing over the land? To this it may be replied, that the forms of the valleys are gentle and rounded, and such as no complication of meteoric causes, that ingenuity can imagine, seems capable of producing that numerous valleys occur on the lines of faults, and that the detritus is dispersed in a way that cannot be accounted for, by the present action of mere atmospheric waters."*

Dr. Buckland has minutely traced the course of quartzose pebbles, from Warwickshire, to Oxfordshire and London, in such a manner as to leave no doubt, that they have been carried down by a violent rush of waters from north to south. For, when we first meet them, in the neighbourhood of Birmingham and Lichfield, they form enormous beds, subordinate to the red sandstone. Thence they have been swept downwards, chiefly along the valleys of the Evenlode and Thames, mixed with fragments of rock existing in Yorkshire and Lincolnshire, but nowhere in situ near the places where the pebbles are now found. The quantity decreases in proportion as we recede from their original bed; so that in Hyde Park, and the Kensington gravel-pits, they are less abundant than at Oxford. But these transported pebbles,

*Page 184. In the first edition, the learned author is more explicit, as he uses the word, "deluge," where now he has, masses of water," in the beginning of the second paragraph.