i?i the Produclion of Valleus. \Qb 



dissemination oF alluvia along the channels and vicinities cyf 

 streams is as eviclLn( and palpiblc as the streams themselves. 

 The immense beds v iui-h lorm the a^stnarics, and still more 

 the deltas of largv nvcrs, at their entrances into {he ocean, 

 are all formations from matter that has travcILd down the 

 respective streams, and vet in all prcbabiiity these enormous 

 quanlititb bear no proportion to those which have passed 

 on into the sea. 



At the mouths of the Rhine and Scheldt, where the public 

 attention is at this time so interestingly engaged, whole 

 and very extensive countries have been formed, from the 

 alluvia brought down by these rivers ; and every other river 

 on the globi' aflbrds the most unequivocal evidence of the 

 vast masses of earthy and stony matter which have travel- 

 led down its waters. Every brook swoln with rain, and 

 every stream occasionally flooded with ten times its usual 

 proportion of water, surcharged to such an excess, with 

 inuddy materials, as frequently to smother iTuiltitudes of 

 fish in their natural element, are all facts which, are con- 

 tinually presenting themselves to our senses ; and yet, if 

 Mr. Farey is to be our guide, all these are palpable decep- 

 tions: the carrying power of streams is all absurdity, and 

 all the endless masses of alluvia which every where accom- 

 pany flowing water, have diopt from the nioon, or travelled 

 up the streams from the sea, but can never have found 

 their way by so easy and natural a course as down them. 



Mr. Farey cannot discover any where in the course of the 

 streams, the bottoms of ancient lakes, .as described in my 

 former paper ; but that I consider as a mere play on the 

 word lake, for he does not assert that the flats which he 

 has inspected do not abound with alluvia, but only that 

 they have not, in his opinion, been the site of former lakes. 

 If Mr. Farey will deny that the flats traversed by streams 

 do abound with alluvial matters, our veracities will then be 

 at issue, not on a matter of opinion, but of fact. I gave a 

 very siniple rule for ascertaining where lakes formerly ex- 

 isted, and had it contained any fallacy, its refutation would 

 have been easy. It was to suppose the present valleys tilled 

 up, the streams still continumg to flow, and then to ob- 

 serve where the water would accumulate mto a lake, and 

 on that s|)(jt alluvia and every other indication of a former 

 lake would now be formed. 



Mr. Farey also speaks of having looked for the beds of 



former lakes ii\ the vallevs, where no one would imaijine 



they ever could have existed, h was on the flats and in 



N i th^ 



