MUSEUM OF COMPARATIVE ZOOLOGY. 13 



REPORT OF THE STURGIS HOOPER PROFESSOR OF 



GEOLOGY. 



By Reginald A. Daly. 



In January the writer returned from France, terminating his 

 leave of absence from the University. The remainder of the year 

 was spent on research work; no courses of instruction were given. 

 During the spring, field studies on recent changes of level along the 

 New England coast were continued. At the invitation of Dr. 

 A. G. Mayor, Director of the Marine Laboratory of the Carnegie 

 Institution of Washington, some weeks were spent in Florida on 

 investigations of: — 1, The causes of the cementation of " beach- 

 rock"; 2, The chemical precipitation of calcium carbonate; and 

 3, The coral reefs of the region. On July 2nd the writer left 

 Cambridge for the Samoan islands, where eight weeks were de- 

 voted to a somewhat detailed mapping of the island of Tutuila 

 and reconnaissance of Ofu, Olosenga, Tau, and Upolu, with 

 special reference to their volcanic geology. The expenses of this 

 work, as of that in Florida, were defrayed by the Carnegie Institu- 

 tion, and in many other, more personal ways, the investigations 

 were greatly aided by Dr. Mayor, to whom the writer's hearty 

 thanks are due. A large collection of igneous rocks was made. 

 A general statement as to the results of the expedition has been 

 sent to press and will appear in the annual report of the Director 

 of the Marine Laboratory of the Carnegie Institution. 



During the year, a paper on the post-Pliocene history of the 

 coral-reef zone was written. Laboratory studies on post-Glacial 

 movements of the earth's crust in the regions peripheral to the 

 Pleistocene ice-caps were continued. Field and other evidence 

 has been found that the isostatic adjustment following the relief 

 of load because of deglaciation has been accomplished by plastic 

 deformation of the earth's body. The peripheral belt surrounding 

 the North American ice-cap was pushed up by the weight of the 

 ice and it sank after the ice was melted. These movements are 

 believed to be important since they seem to explain floral and 

 faunal peculiarities of certain islands, including Newfoundland, 

 and also certain abnormalities in the drainage of the peripheral 

 belt extending from the Hudson river to the Platte river. 



