Why does the sea constantly occupy a basin within the limits which contain it, and there separate the dry parts of the surface of the globe always projecting above it?
3.

Has the ocean basin always existed where we actually see it, and if we find proofs of the sojourn of the sea in places where it no longer remains, by what cause was it found there, and why is it no longer there?
4.

What influence have living bodies exerted on the substances found on the surface of the earth and which compose the crust which invests it, and what are the general results of this influence?
Lamarck then disclaims any intentions of framing brilliant hypotheses based on supposititious principles, but nevertheless, as we shall see, he falls into this same error, and like others of his period makes some preposterous hypotheses, though these are far less so than those of Cuvier's _Discours_.

He distinguishes between the action of rivers or of fresh-water currents, torrents, storms, the melting of snow, and the work of the ocean.

The rivers wear away and bear materials from the highlands to the lowlands, so that the plains are gradually elevated; ravines form and become immense valleys, and their sides form elevated crests and pass into mountain ranges.
He brings out and emphasizes the fact, now so well known, that the erosive action of rain and rivers has formed mountains of a certain class.
"It is then evident to me, that every mountain which is not the result of a _volcanic irruption_ or of some local catastrophe, has been carved out from a plain, where its mass is gradually formed, and was a part of it; hence what in this case are the summits of the mountains are only the remains of the former level of the plain unless the process of washing away and other means of degradation have not since reduced its height." Now this will apply perfectly well to our table-lands, mesas, the mountains of our bad-lands, even to our Catskills and to many elevations of this nature in France and in northern Africa.