184 
ARE SOILS ENRICHED, IMPOVERISHED, [Part III. 
Lyell himself, though the doing so I feel to be 
as audacious a sacrilege as if I were to attack an 
astronomical opinion of Newton’s. 
It is true that the direct action in waste and 
denudation of torrents and rivers is on lines 
only: and were it not for the lateral wash of 
rain, this their direct action would only cut 
ravines and channels to the sea; that is, where 
a spring issues high up the rocky mountain-side 
it will cut a deep ravine, and the deeper it cuts, 
the more springs it will lay open. But what 
widens this ravine into a broad valley with gently 
sloping sides ? The lateral wash of rain into the 
longitudinal valley. 
And what forms the broad valley even where 
there is no river at the bottom ? or within many 
miles? The longitudinal scooping power of the 
concentrated rush of rain which in no respect 
differs from that of the torrent, except in its 
being a hundredfold more powerful than the 
torrent. It is indeed intermittent: so is the real 
scooping force of the torrent; for torrents only 
really excavate when swollen by rain. A torrent 
swollen by rain to perhaps twenty times the 
volume of its usual spring water, and hurling 
fragments of rocks along of all sizes, is in point of 
excavating and destructive power as much more 
