And then he remarks that "indeed in many mountains, and especially in the Pyrenees, in the very centre of these mountains, we observe that the strata are for the most part either vertical or so inclined that they more or less approach this direction." "But," he asks, "should we conclude from this that there has necessarily occurred a universal catastrophe, a general overturning?
This assumption, so convenient for those naturalists who would explain all the facts of this kind without taking the trouble to observe and study the course which nature follows, is not at all necessary here; for it is easy to conceive that the inclined direction of the beds in the mountains may have been produced by other causes, and especially by causes more natural and less hypothetical than a general overturning of strata." While streams of fresh water tend to fill up and destroy the ocean basins, he also insists that the movements of the sea, such as the tides, currents, storms, submarine volcanoes, etc., on the contrary, tend to unceasingly excavate and reestablish these basins.

Of course we now know that tides and currents have no effect in the ocean depths, though their scouring effects near shore in shallow waters have locally had a marked effect in changing the relations of land and sea.

Lamarck went so far as to insist that the ocean basin owes its existence and its preservation to the scouring action of the tides and currents.
The earth's interior was, in Lamarck's opinion, solid, formed of quartzose and silicious rocks, and its centre of gravity did not coincide with its geographical centre, or what he calls the _centre de forme_.

He imagined also that the ocean revolved around the globe from east to west, and that this movement, by its continuity, displaced the ocean basin and made it pass successively over all the surface of the earth.
Then, in the third chapter, he asks if the basin of the sea has always been where we now actually see it, and whether we find proofs of the sojourn of the sea in the place where it is now absent; if so, what are the causes of these changes.

He reiterates his strange idea of a general movement of the ocean from east to west, at the rate of at least three leagues in twenty-four hours and due to the moon's influence.