1872.] daavkijrs — classification of pleistocene strata. 439 



15. Relation of the Pleistocene Mammalia to the Glacial 

 Period. 



The relation of the Pleistocene mammalia to the Glacial age, or 

 the age of maximum cold, miist now be considered. Did they invade 

 jSTorthern and Central Europe during the first or the second Glacial 

 period, before or after the marine submergence indicated by the 

 " middle drift " ? "We might expect, a priori, that as the tem- 

 perature became lowered, the northern mammalia would gradually 

 invade the region occupied before by the Pliocene forms ; and such 

 a mingling of Pleistocene and Pliocene animals we find in the pre- 

 glacial forest-bed. Traces of such an occupation would necessarily 

 be very rare, since they would be exposed to the grinding action 

 both of the advancing glacial sheet, and, subsequentlj-, to that of 

 the waves on the littoral zone during the depression and reeleva- 

 tion of the land. At the time also that the greater part of Great 

 Britain was buried under an ice-sheet they could not have occupied 

 that region, although they may have been, and most probably were, 

 living in the districts further to the south, which were not covered 

 with ice. The labours, however, of Dr. Bryce and others have proved 

 that one at least of the characteristic Pleistocene mammalia, the 

 mammoth, as well as the reindeer, lived in Scotldan before the de- 

 posit of the Lower Boulder-clay ; while Mr. Jamieson has pointed out 

 that these animals could not have occupied that area at the same time 

 as the ice, and therefore must be referred to a still earlier date. Dr. 

 Falconer has shown that the mammoth occurs in the Porest-bed ; and 

 his conclusion, which seemed to be doubtful, has been verified by fresh 

 discoveries. The teeth and bones discovered in the ancient land- 

 surface at Selsea also very probably indicate that the mammoth 

 lived in Sussex before the glacial submergence, although they were 

 never admitted by Dr. Falconer to be of the same age as the 

 remains of Elephas antiquus from the same Pregiacial horizon. On 

 a careful reexamination of the Avhole evidence, I am compelled to 

 believe with Mr. Godwin- Austen and Mr. Prestwich that the a priori 

 argument that Pleistocene mammalia occupied Great Britain before 

 the Glacial period is fully borne out by the few incontestable proofs 

 that have been brought forward of the remains having been found 

 in Pregiacial deposits. And the scanty evidence on the point is 

 just what might be expected from the rare accidents under which 

 the bones in superficial deposits could have escaped the grinding 

 . of the ice-sheet, and the subsequent erosive action of the waves on 

 the coast-line. The arrival of the northern and temperate Pleistocene 

 mammalia in Britain in Pregiacial times implies that they were 

 living on the Continent before the low glacial temperature had set in. 

 On the other hand the evidence is conclusive that they lived in Bri- 

 tain and on the Continent after the intense glacial cold had passed 

 away, since their remains are found in deposits which rest on Boulder- 

 clays. At Schussenried, for examiDle, the reindeer, glutton, bear, 

 and other animals were found by Prof. Fraas in a deposit which 

 rested on the surface of the terminal moraine of the glacier of the 



