XCll PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



exist between the Faunas and the Floras of what we are accustomed 

 to call geological periods. As we have already learnt that the 

 fauna of one period was not destroyed before the creation or in- 

 troduction of that of the succeeding period, so now we learn that 

 those forms of animal life which roamed over the surface of the 

 earth before man came to exercise dominion over them, were not, 

 as was at one time supposed, destroyed before his arrival, but con- 

 tinued to coexist with him, until the time came when they were 

 to make way for other forms more suited to the new conditions 

 of life and to his requirements. 



But I must, however briefly, allude to the papers read before the 

 Hoyal Society by Mr. Prestwich, and published in the ' Philosophical 

 Transactions' last year, giving tis the results of his investigations 

 respecting the geological position and age of the flint-implement- 

 bearing beds, and of the causes to which they are to be attributed. 

 He shows that river-action, as it now exists, could not have exca- 

 vated the present valleys and spread out the old alluvia. Nor 

 does he admit purely cataclysmic action in cases Avhere the evi- 

 dences of contemporaneous old land surfaces and of fluviatile 

 beds are so common. But with river- action of greater intensity, 

 and periodical floods imparting a torrential character to the 

 rivers, he considers that the phenomena admit of more ready 

 explanation. 



"Without attempting to go into the interesting details contained 

 in these papers, I will merely quote one passage which embraces 

 the conclusions at which he has arrived. "I conceive," he says, 

 " that the hypothesis brought forward in this paper gives consist- 

 ency to the whole subject. It brings down the large mammalia 

 to a period subsequent to that when the extreme glacial conditions 

 prevailed, and closer to our own times ; it places all the old river 

 allmda in the same period, and groups together the previously 

 isolated fluviatile beds of Grrays, Brentford, and other places in 

 England, together with the loess and various sables lacustres and 

 diluviums of French authors ; it connects the great platform-ter- 

 races of gravel, skirting so many of our river- valleys, with the 

 same period, and makes the connexion between these, and the 

 excavation of the valleys themselves as well as the formation of the 

 loess, dependent upon one prolonged and uniform set of operations, 

 in accordance with the climatal conditions and necessarily resulting 

 from them." 



With regard to the geological age of these deposits, Mr, Prest- 

 wich shows that they were subsequent to the period of theBoulder- 

 clay deposits, and he concludes his paper with some interesting 

 remarks on the uninterrupted succession of life from this post- 

 pliocene period to our own time, as evidenced by the direct de- 

 scent of a portion of the old fauna to our day, though he cannot 

 explain why the larger Pachyderms should not also have survived. 



Would it be rash to suggest as an answer to this question the 

 possibility of their having been destroyed during the glacial 

 period, and that the bones of Elephants and E/hinoceros now found 



