24 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1921. 



indeed of the world. He was for many years connected with the 

 United States Geological Survey, and for a time professor of 

 petrology in the University of Chicago. He was the author of two 

 privately printed volumes on Rock Minerals and Igneous Eocks 

 and numerous papers in the Government reports. He was also a 

 joint author of the Quantitative System of Eock Classification. 

 The important collections made and studied by him are all in the 

 custody of the National Museum. 

 Eespectfully submitted. 



Charles D. Walcott, Secretary. 



