Popular Science Lectures. 435 
by the fact that the districts inhabited by him during the 
vast period of the glacial epoch, are now sunk beneath the 
sea — these lands being originally laid bare by the locking 
up, in the form of the ice of the great Ice Age, of a quantity 
of water that would cause a depression of the level of the 
sea of nearly two thousand feet, and which lands became 
again submerged by the melting of the ice at the end of 
the glacial period. The probable origin of life during 
the early ages of the earth under unique thermal condi- 
tions, and the probable differentiation of the animal and 
the vegetable organisms, were suggested ; and it was 
insisted on that, considering the history of the evolution 
of animals as based on the increasing complexity of 
organisation from the lowest to the highest types, the 
highest in their development presenting a summary, so to 
speak, of their ancestry, and considering the geological 
record that, as the ages of the past rolled by, new and 
higher types of animals successively appeared, it was to 
be inferred that, in the far distant future, when this 
present period would be, in the history of the earth, but 
a past geological age of high antiquity, a race of beings 
would be found upon the earth, as superior to the species 
" man," as man is at the present to the lower types. 
The leclure was illustrated by a large colleclion of 
diagrams and prepared specimens, shewing the chief 
types of, and the transitional links between, the various 
classes and orders of the Animal Kingdom. 
3J 
