SAMUEL CALVIN 391 



we will never blame anyone not familiar with it in the field for 

 denying its existence; but, whatever the explanation, there is a con- 

 sistent and co-ordinate set of phenomena that demands explanation, 

 and that is best interpreted by the hypothesis of a separate Iowan 

 ice sheet." 



Aside from his work at the university and on the Iowa Survey 

 Calvin did his full share in the general work of his chosen profes- 

 sion. While he was not especially interested in economic geology, 

 his advice was sought and valued by a number of Western mining 

 companies ; he was a member of the first Conservation Conference 

 at the White House; he served on the National Advisory Board 

 on Fuels and Structural Materials; he was an active member and 

 officer of numerous professional societies, including the Geological 

 Society of America, of which he was president in 1908; he was 

 one of the founders of the American Geologist, and of the Associa- 

 tion of State Geologists; and in many other positions he made his 

 influence felt. He was a charming writer, a popular lecturer, and 

 a most inspiring teacher. His personal influence was strong and 

 deep, and the thousands of students who came into contact with 

 him are today better men and women because he lived. He left 

 a stainless record as a man and citizen, and an inspiring example 

 to young men of the profession. 



