EVOLUTION. 31 



insects die out. Thus the adaptation of flowers to 

 insects, and the formation of new species by cross- 

 fertilization, is found to be due to Natural Selection, 

 not to special creative design that formed them in 

 their present shape and color. 



Geology. 



Geology gives the strongest support to the theory 

 of Evolution. The life-bearing rocks are supposed 

 to represent a thickness of about 1 30,000 feet. These 

 rocks were formed from deposits of ooze, at the 

 bottom of the waters, which gradually hardened into 

 stone. Vast ages were required for these formations, 

 and for the elevations and depressions which they 

 have undergone. In the lower half of these strata the 

 only forms of life are of the lowest order, and the 

 vegetable life is mainly of sea-weeds. In the next 

 hiofher strata we find the remains of fishes and ferns. 

 Above these come reptiles and pine forests, and 

 birds first appear ; and here the intermediate form 

 is found of birds with toothed jaws and lizard's tail. 

 The first sign of mammals is found here, the teeth of 

 a small animal of the kangaroo type. In still higher 

 strata appear mammals and leaf forests, and the 

 animals nearest to man are found. Finally, in the 

 latest deposit we find the remains of man and of cul- 

 tivated forests. But this era of man is not one two- 

 hundredth part of the vast ages through which or- 

 ganic life has existed, and he appears only as the high- 



