oW on the Origin of the Valleys of Auvetgne. 219 



that of the former, the true question being, whether it be most 

 easy to account for the absentee of such pebbles in the one case, 

 on the supposition of a general deluge, or their presence in the 

 other, if we deny such an event to have taken place ? 



Let us suppose a Saussure or a Deluc, fresh from the Alps; 

 to come to England uninformed ^th tes^t ta the particular 

 spots in which the diluvial gravel of this country has been found 

 to contain rolled blocks derived from strata not met with in 

 their neighbourhood. It is very possible that, under these cir- 

 cumstances, he might, in his first researches, light upon a disr- 

 trict in which no such evidences of a distant current of water 

 were to be found, or in which they were so rare, that, during 

 a cursory visit, and with his attention divided by other ob- 

 jects, they should be overlooked. Yet it would be rash for 

 him, in such a case, either to conclude that the valleys of Great 

 Britain in general were formed by a different Cfluse from those 

 in the Alps, or, having persuaded himself by the phenomena 

 exhibited amongst these his native mountains, that similar ope- 

 ration^ must have been^^neral in other countries, to conclude 

 that the particular spot hfe bad chanced to examine, constituted 

 an exception to the rule* ' ' < n 



Even so, I contend that English g^olog^st&,YpiS(ll*g fr6m a 

 country where the phenomena of diluvial action have been 

 much studied, to one where they have been in a great degree 

 neglected, ought not to be startled, if the first districts on which 

 they chance to pitch, fail to present direct evidence of the kind 

 they are in quest of. They should rather conclude, that the 

 diluvial currents may have acted with their greatest force in a 

 different direction, and have therefore transported the blocks in 

 question elsewhere, and consequently be disposed to attribute 

 the gravel, in this instance, to the same cause which they assign 

 to it in other places, tvhere more decided proofs of its origin are 

 discoverable. 



Such appears to be the line of argument which geologists 

 have adopted in other analogous cases. Thus, when they have 

 observed two contiguous valleys, the one placed under circum- 

 stances that appear to them to exclude the action of present 

 streams, the other explicable by this supposition, equally as by 

 that of the operation of a deluge, they have considercnl them- 



