12 ANNUAL REPORT OF THE 



REPORT OF THE STURGIS HOOPER PROFESSOR OF 



GEOLOGY. 



By Reginald A. Daly. 



During the year the writer continued to act as Chairman of the 

 Department of Geology and Geography, as instructor in charge of 

 Geology 4, and as the conductor of research in Geology 20c. The 

 time was chiefly spent on investigations regarding the earth's 

 thermal gradient, elasticity, and viscosity; on the strength of the 

 earth's crust; on the nature and amount of the tangential stresses 

 affecting the crust ; and on the distribution of densities within the 

 earth. These studies have led to the conclusion that the theory 

 of mountain-building should take serious account of the new 

 Taylor- Wegener hypothesis of continental creep. A manuscript 

 on the subject has been written, but further work is needed before 

 it can be published. Some results of the investigation were 

 presented before the Geological Society of Washington. 



On July 2nd the writer sailed for England, to pursue certain 

 field studies on the geology of Great Britain and, as Director of the 

 projected Shaler Memorial Expedition to South Africa, to complete 

 arrangements for the transportation of the party and for its equip- 

 ment. 



The writer continued to serve as a member of the Division of 

 Geology and Geography in the National Research Council, and as 

 a member of the American Geophysical Union, meetings of which 

 were attended at Washington. In the May number of the Ameri- 

 can journal of science, a paper was published on the Postglacial 

 warping of Newfoundland and Nova Scotia. 



