DILUVIAL DEPOSITES. 



131 



a powerful current of water swept over the surface 

 of the earth. Professor Hitchcock remarks, that 

 in an agricultural point of view it is the least in- 

 teresting of all our strata; for, of all the soils, it is 

 the most unfriendly to rich vegetation ; and as it is 

 spread, in a good measure, over every kind of rock, 

 it often prevents the formation of a good soil from 

 the decomposition of the rock. It is, in general, 

 easily recognised in the most steril places, in the 

 form of low, rounded hills, composed almost en- 

 tirely of coarse pebbles or cobble stones, and some- 

 times larger rounded masses of rocks called bowl- 

 ders, mixed with coarse sand and covered with a 

 stinted vegetation. It was evidently deposited by 

 currents rushing violently over the surface, since 

 only the coarser materials which were driven along 

 were left, while the finer particles were kept sus- 

 pended by the agitation of the waters. Some va- 

 rieties of this diluvium may indeed be converted 

 into a soil of tolerable richness, by manuring it 

 abundantly and clearing away the stones. And 

 generally, too, the rains that have fallen on it for 

 thousands of years have conveyed its finer parti- 

 cles to the bottom of the valleys and cavities with 

 which this formation abounds ; and these being 

 mixed with much vegetable decayed matter, a soil 

 of good quality is formed. But these fertile spots 

 ought rather to be denominated alluvium than dilu- 

 viumy 



Mr. Lyell, however, refers diluvial as well as aU 

 Invial deposites to the action of causes now in op- 

 eration ; but he acknowledges that his theory re- 

 quires " thousands of centuries" to account for the 

 present appearances on the surface of the earth. 

 As such a deposite, however, might have been pro- 

 duced by a general deluge, and as there are no facts 

 in geology which render such a catastrophe improb- 

 able, and we are, moreover, expressly told in scrip- 

 ture that such an inundation did happen at the time 



