Part III.] OR POISONED BY VEGETABLE GROWTH? 
183 
logical sense), is in perpetual formation over the 
whole surface of the earth; and from the whole 
surface of the earth it is in perpetual movement, 
by the wash of rain, to the bottom of the sea. 
In opposition to Professor Sedgwick’s opi¬ 
nions, that “ Torrents and rivers act upon lines 
only ,” while vegetable growth and deposit are 
universal, the area of aqueous denudation, or 
the wash of rain water, which is carried off by 
rivers, is still more universal than the area of 
vegetation. The disintegration of the barest 
rocks, of the barest mountain-ridges, beyond 
the pale of vegetation, is washed by rain to the 
plant-clothed hill-side below. Nay, even from 
the mountain-top clad with eternal snow, the 
descent of this en masse , the avalanche, and the 
glacier, bring down d4bris with them to be dis¬ 
integrated below. Indeed, glaciers bring their 
huge quota ready-ground for exportation; and 
if my admiration and reverence for the great 
master would allow me, I should say that Lyell 
made an error in admitting this vast error of 
the Professor’s; that is (though Lyell controverts 
Sedgwick’s opinions), in allowing the expression 
which I have marked to pass current. Nay, as 
regards the formation of valleys, I would actually 
impugn some favourite doctrines of the great 
N 4 
