ZOOLOGY OF FOSSIL REMAINS 105 



human and the simian lines have had an independent 

 development for many centuries. There has been 

 no crossing of the lines since Tertiary times. 



The derivation of man from an extinct Tertiary 

 Primate seems already to be well authenticated. 

 Furthermore, the fossil records give evidence of the 

 conditions under which the development of the 

 higher races of animals began. By making plastic 

 casts of the interior of the fossil skulls of Tertiary 

 mammals, it has been determined that there was in 

 that geological period a marked increase in the size of 

 the brain. This circumstance was of the greatest 

 importance both for progress and for perpetuity of 

 certain kinds of animals. Those, in particular, whose 

 increased intelligence enabled them to cope more 

 successfully with the conditions of their existence, 

 and to turn natural forces to their advantage, were 

 continued and improved. In pre-humans the increase 

 in brain surface led to the power of storing up im- 

 pressions, and, finally, brought about a condition of 

 educability which formed the starting point for 

 marked improvement. 1 



1 The above 14 paragraphs quoted from the writer's Biology and Its 

 Makers. 



