16 
The Ancient Fauna of Essex. 
seems to be tliis: these animals were not only more active, 
but the majority of them were nocturnal in their habits ; and 
no doubt when the Herbivora were overtaken by floods it was 
frequently in the night when they were asleep—-just the 
time when the Tigers, Lions, Bears, and Wolves would be 
wide awake; and they would probably get up the nearest tree 
or escape to the higher ground, or some other suitable place, 
and so avoid the catastrophe. And, indeed, many of them 
must have escaped, or we should have a far larger proportion 
of their remains; though it must always be borne in mind 
that one pair of Lions or one pair of Bears occupied a very 
large tract of country; and therefore we should not expect 
them to be in such numerical abundance as the Herbivora on 
which they fed. 
It may be interesting to inquire how it happens that the 
remains of both northern and southern forms are found com¬ 
mingled together in these deposits. When those immense 
herds of Mammoths occupied the North Sea Valley and the 
adjacent countries, it seems probable that the conditions of 
climate in the extreme North of Europe and Asia had 
previously become unbearable for them, and they had been 
driven south. At any rate, if they did not remain all the 
year, they migrated south every winter. All the Arctic 
species would come down into this country for the winter, 
and stay here until the summer invited such animals as 
the Reindeer, the Elk, and the Musk-Ox to migrate north¬ 
ward in great herds, as they do at the present day on the 
Continent, towards the feeding grounds, which in winter are 
uncongenial to them, but in summer afford them rich 
pasturage. In the same way, in the summer season, the 
Rhinoceros, the Hippopotamus, and other more southern 
animals, with great herds of Wild Horses, would no 
doubt advance northwards and westwards with the change 
of season. Such climatal and physical conditions enable 
us to explain that curious admixture of animal-remains 
found in these deposits, which otherwise would not be 
so easy to comprehend. We are moreover confirmed 
in this view by the fact that we find the same state 
