FLOWEK DISCOVERIES OP FLINT IMPLEMENTS. 457 



those beds were deposited by the agency of rivers involves so many 

 difficulties and objections, that it can hardly be accepted without 

 much further consideration than the subject has received, much as 

 it has been discussed. Indeed, imless we are prepared to admit that 

 all the Quaternary gravels were brought to their present places of 

 deposit by the agency of rivers (which is evidently impossible), it is 

 unreasonable to attribute to that agency any particular portion of 

 those gravels merely because they happen to contain implements. 



Considerable differences of opinion exist between Prench and 

 English geologists as to the causes which led to the accumulation 

 and distribution of those superficial drifts in the south-east of 

 England and north of France of which the flint-implement-bearing 

 beds form part : while the Erench geologists unanimously attribute 

 them to some kind of cataclysmal or diluvial action (although they 

 differ among themselves as to its particular character), the English 

 geologists are nearly unanimous in ascribing them to the action of 

 existing rivers, or at least of rivers which then ran in the same 

 direction as they now do, and drained the same areas. The present is 

 not a convenient occasion for considering this subject at any length. 

 I propose only to show how inadequate, as it seems to me, is the 

 theory of fluviatile transport to explain the condition of the deposits 

 before referred to and of others of a like character. 



The opinion of English writers cannot be better stated than in 

 the words of Mr. Prestwich, from the able and exhaustive memoir 

 upon the flint-implement deposits read by him before the Eoyal 

 Society in 1862. He says, " that certain beds of gravel, at various 

 levels, follow the course of the present valleys, and have a direction 

 of transport coincident with that of the present rivers, and that the 

 extent and situation of some of these beds so much above existing 

 valleys and river- channels, combined with their organic remains, 

 point to a former condition of things when such levels constituted 

 the lowest ground over which the waters passed ; " further, "that the 

 size and quantity of debris afford evidence of great transporting 

 power ; while the presence of fine silt, with land shells, covering 

 all the different gravel -beds, and running up the combes and capping 

 the summit of some of the adjacent hills to far above the level of 

 the highest of these beds, points to floods of extraordinary magni- 

 tude ;" that " these conditions, taken as a whole, are compatible 

 only with the action of rivers flowing in the direction of the present 

 rivers, and in operation before the existing valleys were excavated 

 through the higher plains, of power and volume far greater than the 

 present rivers, and dependent upon climatal causes distinct from 

 those now prevailing in these latitudes"; and he adds that " such a 

 result might formerly have been obtained, 1st, by a direct increase 

 in the rainfall ; 2ndly, by the accumulation and rapid melting of the 

 winter snow, or by the two causes combined ; and 3rdly, by the fall 

 of rain in the spring while the ground was in a frozen state." 



Mr. Prestwich's opinions have been acquiesced in both by Sir Charles 

 LyeU and Sir John Lubbock. The latter, in his preface to the recent 

 English edition of Sven Nilsson's ' Primitive Inhabitants of Scan- 



