ON THE ALLUVIAL DEPOSITS. 365 



while it is universal in the alluvia of rivers. But when 

 the exact rocks with which they exclusively corres- 

 pond, can be discovered at a distance, if also these are 

 of a rare and singular nature, and, more particularly 

 when their place coincides with what might, for other 

 reasons, he imagined the direction of such a current, 

 still taking care to exclude all possible rivers, the evi- 

 dence is commonly as good as can be expected. If 

 such "diluvian" deposits have been named in England, 

 I must refer the reader, not to the statements, but to 

 the proofs adduced : in Scotland, they are extremely 

 difficult to prove ; while if I think that I have seen 

 them anywhere, it is, possibly, in the central High- 

 lands, where they might have rested, during an equally 

 possible flow of water over the exterior country. If 

 I were asked for another probable or possible example, 

 it is the northern extremity of the Isle of Mann ; yet 

 even this may be a deposit from tide currents, under 

 changes of level : and I name this striking instance 

 here, as a caution respecting similar cases. 



But let this never be forgotten, neglected as it 

 .seems to have been, that no alluvia from such a cause 

 can ever be stratified, or separated into layers of fine 

 and coarse materials, in any manner : while if that 

 had been remembered, or known, we should have had 

 fewer reports of "diluvian" alluvia. And I am bound 

 to add, that the adduced instances of " diluvian" de- 

 posits have not carried conviction to many, that, 

 among the most active observers of the continent, the 

 belief in diluvia is far from prevalent, and that there 

 are some who deny the occurrence of any other ex- 

 tensive alluvia than those which occupy vallies as the 

 probable produce of running waters or powerful casual 

 and local torrents. The evidence supposed to be de- 

 rived from organic interred remains has been exa- 



