324. Though there can be no doubt of the justness of the preceding conclusions, when applied to lakes in general, some apparent exceptions occur, in which the progress of draining and filling up seems to have been suspended, or even to have gone in a contrary direction. These exceptions consist of the lakes which appear to have received a greater quantity of materials than was sufficient to have filled them up. Such, for example, is the Lake of Geneva, which receives the Rhone descending from the Valais, one of the deepest and longest valleys on the surface of the earth. Now, if this valley, or even a large proportion of it, had been excavated by the Rhone itself, as our theory leads us to suppose, the lake ought to have been entirely filled up, because the materials brought down by the river seem to be much greater than the lake, on any reasonable supposition concerning its original magnitude, can possibly have received. What, then, it may be said, has become of all that the Rhone has brought down and deposited in it? The lake, at this moment, retains, in some places, the depth of more than 1000 feet; and yet, of all that the Rhone carries into it, nothing but the pure water issues. If it has been continuing to diminish, both in superficial extent and in depth, from the time when the Rhone began to run into it, what must have been its original dimensions? I cannot pretend to remove entirely the difficulty which is here stated; yet I think the following remarks may go some length in doing so. 325. It is certain, that from the present state of the Lake of Geneva, and of the ground round it, we can hardly draw any inference as to its original dimensions. Saussure has traced, with his usual skill, the marks of the course of the Rhone, on a level greatly above the present; and, by observations on the side of Mont Saleve, has found proofs of the running of water, at least 200 toises above the present superficies of the lake. But, if ever the superficies of the lake stood at this height, or at this height nearly, though we can conjecture but little concerning the state of the adjacent country, which no doubt was also on a higher level, the lake may very well be supposed to have been of far greater dimensions than it is now. It may have occupied the whole space from Jura to Saleve, and included the Lake of Neufchâtel; so that it may have been of magnitude sufficient to receive the spoils of the Valais, which, as the surface of its waters lowered, may have been washed away and carried down to the sea. Thus it may have afforded a temporary receptacle for the _debris_ of the Alps, and may have served for an _entrepot_, as it were, where those _debris_ were deposited, before they were carried to the place of their ultimate destination.