Changes in Geography and Climate. 47 
country, at the close of the Glacial Epoch, it was far 
easier for animals and plants to cross from the Continent 
than it is now. 
The reader will probably rise from the perusal of this 
chapter with a confused idea of many small changes in 
the limits of sea and land; which, however, were of no 
very great importance as bearing on the past history of 
our flora. This impression is, I believe, the correct one; 
for, after twenty years’ work at deposits belonging to the 
periods here dealt with, I am greatly impressed with the 
smallness and multitude of the changes, and with the 
- gradual way in which they occurred, as is demonstrated 
wherever we can discover continuous records. The 
climatic changes, on the other hand, though perhaps 
equally gradual, were most thorough and sweeping; 
inevitably they must have been accompanied by corre- 
sponding changes in the flora. 
