SAMUEL CALVIN 389 



In scientific research, Calvin's personal interest lay mainly in 

 paleontology and, in later years, in the study of the Pleistocene 

 deposits. Aside from contributions to the paleontology of the 

 Paleozoic invertebrates, Calvin will probably be best remembered 

 for the discovery of the fauna of fish remains in the Devonian beds 

 near Iowa City, and for his studies of the vertebrate remains of the 

 Aftonian deposits. The fish remains have been investigated by 

 C. R. Eastman, who found in them much of interest. The Afto- 

 nian bones are important because they permit fixing the age of a 

 widely scattered series of puzzling deposits. In his last published 

 administrative report 1 Calvin speaks of them as follows: 



This remarkable interglacial fauna is not altogether new to science. The 

 individual species, and to some extent the fauna as a whole, have for some 

 time been known to students of paleontology. It has also been known that 

 some of the species were at one or more times inhabitants of Iowa. But, so 

 far as concerns Iowa, it was not known that the few discovered forms, which 

 heretofore have been represented by isolated finds, were contemporaneous; 

 and outside of Iowa, in territory ranging from Texas to western Nebraska, 

 the exact age of the beds in which the remains of this assemblage of extinct 

 mammals were found was not definitely fixed. The fauna as a whole is 

 markedly different from that familiar to the pioneer settlers of this State, 

 very different from that known to the pioneers in any part of America. True 

 horses were represented by at least two species, both quite distinct from our 

 domestic species; there were three species of elephant, one of imperial size, 

 and there were two mastodons, making in all five great proboscidians; there 

 was at least one species of camel, an extinct bison, a gigantic stag, and two 

 ponderous, awkward, clumsy ground sloths. The smallest of the three ele- 

 phants seems to be identical with the hairy elephant or northern mammoth 

 of Europe and Asia; it furnishes to this unique fauna a distinctly boreal 

 element. The two great sloths, on the other hand, contribute an element 

 distinctly South American. As found in Iowa, the age of the fauna is definite 

 and clear. The beds in which the remains occur belong to the Aftonian stage; 

 these animals lived, and the beds in which their remains were buried were 

 laid down, in an interval of comparatively mild climate between the first 

 and second stages of Pleistocene glaciation. 



The quotation illustrates at once Calvin's broad scientific 

 interest and the singular clearness of his writings, which makes it 

 a pleasure to readers and a fit model for beginners. 



Calvin's active interest in the Pleistocene deposits dates from 



1 Iowa Geol. Surv., XX, xxii. 



