Nothing can be more absurd than to suppose a collection of shells and corals, amassed about the primitive mountains of the earth, to become mountains equally solid with the others, upon the removal of the sea; it would be inconsistent with every principle of sound reasoning to suppose those masses of loose materials to oppose equal resistance to the wasting and destroying operations of the surface of the earth, as do those pretended primitive masses, which might be supposed endued with natural hardness and solidity; yet, consult the matter of fact, and it does not appear that there is any difference to be perceived. There are lofty mountains to be found both of the one kind and the other; both those different masses yield to the wasting operations of the surface; and they are both carried away with the descending waters of the earth. It is not here meant to affirm, that a mass of marble, which is a calcareous substance, opposes equal resistance, whether to the operations of dissolution or attrition, as a mass composed of granite or of quartz; it is only here maintained that there are in the Alps lofty mountains of marble, as there are in other places lower masses of granite and its accompanying schistus. But that which is particularly to be attended to here is this: In all countries of the earth, whether of primitive masses or those of secondary formation, whether uniform and homogeneous, or compound and mixed of those two different kinds of bodies, the system is always the same, of hills and valleys, lakes and rivers, ravines and streams: no man can say, by looking into the most perfect map, what is primary or what secondary in the constitution of the globe. It is the same system of larger rivers branching into lesser and lesser in a continued series, of smaller rivers in like manner branching into rivulets, and of rivulets terminating at last into springs or temporary streams. The principle is universal; and, having learned the natural history of one river, we know the constitution of every other upon the face of the earth. Thus all the surface of this earth is formed according to a regular system of heights and hollows, hills and valleys, rivulets and rivers, and these rivers return the waters of the atmosphere into the general mass, in like manner as the blood, returning to the heart, is conducted in the veins. But as the solid land, formed at the bottom of the sea or in the bowels of the earth, could not be there constructed according to that system of things which we find so widely pursued upon the surface of the globe, it must be by wasting the solid parts of the land that this system of the surface has been formed, in like manner as it is by the operations of the sea that the shape of the land is determined, upon the shore.