Appendix A 365 



animals, conclude that at different periods the United 

 States and almost every other portion of the earth were 

 connected by land and severed from all other regions by 

 water — ^and, from the study of certain other groups of 

 animals, arrive at directly opposite and incompatible 

 conclusions. 



The most brilliant and unsafe exponent of this school 

 was Ameghino, who possessed and abused two gifts, 

 both essential to the highest type of scientist, and both 

 mischievous unless this scientist possess a rare and ac- 

 curate habit of thought joined to industry and mastery 

 of detail: — ^namely, the gift of clear and interesting 

 writing, and the gift of generalization. Ameghino 

 rendered marked services to paleontology. But he gen- 

 eralized with complete recklessness from the slenderest 

 data ; and even these data he often completely misunder- 

 stood or misinterpreted. His favorite thesis included the 

 origin of mammalian life and of man himself in south- 

 ernmost South America, with, as incidents, the belief that 

 the mammalian-bearing strata of South America were of 

 much greater age than the strata with corresponding re- 

 mains elsewhere; that in South America various species 

 and genera of men existed in tertiary times, some of them 

 at least as advanced as fairly well advanced modern 

 savages ; that there existed various land bridges between 

 South America and other southern continents, including 

 Africa; and that the ancestral types of modern mammals 

 and of man himself wandered across one of these bridges 

 to the old world, and that thence their remote descen- 

 dants, after ages of time, returned to the new. In addi- 

 tion to valuable investigations of fossil-bearing beds in 



