OF THE SEA AND LAND. 9 



"diluvian" origin, especially by those who seek physi- 

 cal information where it was never intended, and is 

 assuredly not to be found. This is to be ignorant of 

 the action of a river, in which the two distinct pro- 

 cesses of laying down and of removing materials are 

 always going on ; while the two effects, which appear 

 to be coexistent in one place, occur, at one point of 

 time, in two places, and are in a state of perpetual 

 transference. The torrent, gradually deepening its 

 rocky bed, carries forward its materials to a lower 

 point, thus diminishing the rapidity of the slope on 

 which it flowed : while^ continuing to act on these, 

 it labours to restore the declivity which it had reduced, 

 thus deepening its channel and transferring them to a 

 lower point. Hence the raising of the bed by the 

 protrusion of materials, and the lowering of it by 

 vertical wear, proceed at the same time : the former, 

 however, preceding the latter, or the work of elevation 

 going on at a point nearer the source, at any instant, 

 than that of deepening. Though the final result would 

 be to equalize the mountain and the sea, the powers 

 gradually diminish, or the time encrease"s, with the di- 

 minution of the declivity, and is thus always most 

 feeble in the plains. But here also it lays down what 

 it will remove, and removes what it has laid down : 

 while the results are modified by lateral deviations ari- 

 sing from the evanescence of the declivity and from 

 obstructions of its own creating ; through the fall of 

 its banks or other causes. Hence arises the depth of 

 deserted alluvia in the wider valleys and the plains, 

 with their permanent elevations above the actual course 

 of the river which created them. And these are the 

 alluvia which some have viewed as "diluvian," as 

 others have supposed them to belong to deserted lakes; 

 unaware of the nature of what I have thus, if too 

 briefly, analysed. The very valley, thus giving an allu- 



