PT. III. OR POISONED BY VEGETABLE GROWTH? 157 



tliem, or no run at all into them. In the last case 

 aerial deposit will fill them, chiefly with leaves. But 

 in all cases aerial deposit forms a great item in filling 

 ponds. 



For the rest, my aerial fancy will be voted incred- Aqueous 



denudation 



ible, because, farther than this, it is invisible. Yet is^^^^iver- 



' ' ' sa], and is 



great effects come from causes which are not very oniy'S^t'he^ 

 visible ; and some people would stare (and among them, teents 



and rivers. 



perhaps,Professor Sedgwick), if you told them that the 

 top of the same Hampshire hill is on one side moving 

 to the German Ocean through the medium of the 

 Thames, and on the other side to the English Channel 

 by the Itch en. Yet from all sides of the tops of these 

 hills, and from all sides of every height on the globe, 

 there are dry river beds, down w^hich soil flows when- 

 ever rain is heavy enough to rim : and all the infinite 

 ramifications of these dry rivers, or ravines, or gorges, 

 or gullets, or combs, or chines, or bottoms, or vales, or 

 dales, or deans, or lavants (qu. from labens), by what- 

 ever name they, or any parts of them are locally called, 

 all have descents graduated by water, and outlets to the 

 running rivers (if not to the sea), without any abrupt 

 junction of the lower ends of the dry valleys with the 

 upper ends of the river valleys ; and no drop of rain 

 runs an inch on the surface of the earth without, as far 

 as it goes, setting some soil forward on its road to the 

 sea. And it w^on't run back again. No return tickets 

 are given. It will wait there, and go on by the 

 nex't-rain, The very soil on which we tread, an(J 



