Such is, in few words, the ordinary action of the water of the sea upon steep coasts, and even that of great masses of water in a state of agitation. M. De Luc, in his various works, has estimated this action with a correctness of observation and of reasoning, which is remarkable only, because it has not been adopted by all naturalists; and few have bestowed the unremitting attention upon the subject which this respectable geologist has done. He has shewn, that the destructive action of the waters upon steep shores, and other coasts or abrupt cliffs, was considerably restrained by the very consequences of this action; that the debris which accumulated protected the lower parts of these coasts from the action of the water, or gradually reduced an abrupt coast to a very inclined and permanent slope. Next, to _torrents_, to rapid and large _rivers_, and to _waves_, it is to _currents_ that a great influence on the earth’s surface has been attributed,--an influence which a highly gifted naturalist, Buffon, has employed to explain all the inequalities of the earth’s surface. Our knowledge of the action of currents is less precise than that which we possess of rivers. But if we cannot so visibly demonstrate that, in no circumstance similar to those which we have specified, do they scoop out the bottom of the sea into valleys, nor form any mountains, we can, at least, conjecture with much probability, and maintain, that we have no direct and constant proof of that action. 4. _Action of Currents._ No one doubts that currents, near coasts, heap up upon the beach, at the mouth of rivers and harbours, pebbles, sand, gravel, mud, or other transportable matters, whether these currents constantly exist, or simply result from the momentary action of a predominating wind; but this action, although already limited to the mobile matters which form the bottom of the sea only in some parts, whether this action, I say, extends to a great depth, that is to several hundred yards, is a question not yet resolved. In the first place, the observation made by mariners, that, in the most violent tempests, the sea is only agitated towards the coasts, or on shallows, and that bodies, sunk to a great depth, (and still what is this depth in comparison with that of the sea,) do not feel the motions of its surface, nor that of currents; and, secondly, reasoning, and even calculation, according to Messieurs La Place and Poisson, concur to shew, that the violent motions of the waters of the sea are not propagated to a great depth. It is therefore probable, that all the transportable matters, which are at this depth, must remain nearly in the position in which they are, since our Continents have assumed their present configuration, unless phenomena and motions of the sea take place at the bottom, of which we are ignorant, and which are foreign to the subject which at present occupies our attention.