60 THE DOCTRINE OF DESCENT. 
IV. 
The Animal World in its Historical and Palzeontological Development. 
IT is so easy to observe that the earth’s crust, from the 
deepest valleys to the highest mountain top contains 
innumerable animal remains, that even antiquity could 
not fail to notice it. But some two thousand years 
passed by before a correct knowledge was attained of 
the relations of these remains to the present world. 
Some thought they were sports of nature, products of 
creative power leading to no special object, but in a 
certain measure to be regarded as exercises prelimi- 
nary to the actual creation of life; others considered 
the fossils as remains of living creatures, indeed, but 
of such as still existed, and which had been destroyed 
by overflows and subsequent withdrawals of the sea. 
The legend of the universal deluge, especially, derived 
great support from this second opinion. Only when, 
at the end of last century, the stratification of the earth's 
crust was revealed to science, after the outlines of a 
history of the solar system and of a special history 
of the earth or geology had been indicated by Kant 
and Laplace, only then arose the possibility and neces- 
sity of a real paleontology, or knowledge of pre- 
historic life. At the beginning of this century it was 
discovered that the fossils corresponding with the stra- 
