186 ' 
ARE SOILS ENRICHED, IMPOVERISHED, [Part III. 
shire, August, 1829, says: “ Some new ravines 
were formed on the sides of mountains where no 
streams had previously flowed*, and ancient river 
channels which had never been filled from time 
immemorial gave passage to a copious flood.” 
And again, Lyell, in giving an account of the 
formation of new ravines by heavy rains on the 
28th of August, 1826, in the White Mountains 
in New Hampshire, says: “ The natural excava¬ 
tions commenced generally in a trench a few 
yards in depth, and a few rods in width, and 
descended the mountains, widening and deepen¬ 
ing till they became vast chasms.” This was the 
effect of one continuous heavy rain. 
And in the present day we may see ravines 
begun by the accidental results of many opera¬ 
tions of man . A hedge or ditch, a pathway, or 
waggon way may commence the furrow on the 
mountain’s brow, nay, even on downs which are 
covered with the closest greensward: and how 
many of our byeroads and lanes become ravines! 
Indeed, as the long conduits whose gradients 
are laid by the wash of rain, very generally 
become the roads or lines of traffic of man, so, 
vice versa , the roads or lines of traffic of man, on 
* “ Quodque fuit campus, vallem decursus aquarum 
Fecit.” 
