218 DARWIN AND PALEONTOLOGY 



Let us begin with the broad and proceed to 

 the minute. 



Selection of entire animals and parts of ani- 

 mals through elimination. Paleontology not 

 only sustains Darwin's broad induction of evolu- 

 tion, but in an equally convincing manner it sus- 

 tains his broad induction that Natural Selection 

 is and always has been one of the dominant prin- 

 ciples of change in the aspect of the living world. 

 Because of the thousands of facts which he mar- 

 shaled from every branch of natural history in 

 support of this factor he is entitled to be regarded 

 as the founder although not as the originator of 

 the law of the survival of the fittest. In study- 

 ing the causes of the extinction of the mammals 

 throughout Cenozoic times/ I have been struck 

 by the fact that there is hardly an hypothesis of 

 extinction suggested by more recent research 

 which escaped the more or less serious attention 

 of Darwin. My general survey of the economy 

 of extinction in this great class of animals cer- 

 tainly establishes the existence of a very great 

 variety of causes of elimination, some of which 

 are internal, some external in origin, while all 

 operate under the broad principle of selection. 

 I beUeve I have found fresh proofs of the con- 

 tinuous operation of selection on all organs, be- 

 cause some new and brilliant instances in addi- 

 tion to those gathered by Kowalevsky and Marsh 



' " The Causes of Extinction of Mammalia," American 

 Naturalist, Vol. XL, No. 479, December, 1906, pp. 769-95; No. 

 480, November, 1906, pp. 839-59. 



