396 
POPULAR SCIENCE REVIEW. 
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 preglacial horizon. On a 
careful examination of the whole 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 first glacier period to be fully borne out by 
the few incontestable proofs that have been brought forward of 
the remains being found in preglacial 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 withstood the grinding of the ice sheet and 
the subsequent erosive action of the waves on the coastline. 
This view seems to me to be more likely to be true than that 
which I have hitherto maintained, that the Pleistocene mam- 
malia arrived here after the marine submergence, and to which 
I had been led partly by the doubts of Dr. Falconer as to the 
age of the mammoth at Selsea, and partly from my own doubts 
whether the clays under and on which the animal was found in 
Scotland belonged to the first or to the second period of glacier 
extension ; while, on the other hand, the postglacial range of 
the Pleistocene mammalia in central and eastern England was 
clearly proved in many cases. 
But whatever view may be held as to the arrival of the 
Pleistocene mammalia in Britain during the lowering of the 
temperature which immediately preceded the first glacier period, 
an examination of the accompanying map (PI. LXXVIII.) will 
prove that they were in full occupation of the low country at 
the time that the higher lands and certain other regions were 
occupied by the ice during the second glacier period. The 
dotted areas are those in which the Pleistocene mammalia 
have been found in Scotland, Ireland, Wales, and England, 
Northern France and Belgium, and which occur equally in 
the bed of the North Sea and in the British Channel ; while 
those areas which are left plain on the map are those which 
are full of the most fresh-looking traces of ice action, old 
moraines, glacial striae, and the like, which have a direct rela- 
tion to the existing valleys. 
The absence of these animals from those areas must have 
been caused by the existence of some barrier to their migra- 
tion ; and the hypothesis that this was the presence of ice 
alone satisfies all the conditions of the case. It accounts both 
for the exceedingly modern aspect of the glacial phenomena, 
and for the irregular distribution of the animals.* We may 
* The authorities for the distribution of the mammalia are to be found in 
my Essay published in “ Quart. Geol. Journ.,” May 1860 . 
