28 ANNUAL REPORT OF THE 



REPORT ON COURSES IN PETROGRAPHY. 



By Professor J. E. Wolff. 



The usual courses were given in Elementary Petrography 

 (Geol. 12) and in Advanced Petrography by Professor Wolff, 

 assisted by Mr. C. L. Whittle. The former course was attended 

 by nine students and the latter by three. 



Original work was carried on by Mr. R. A. Daly in the prepa- 

 ration of a Monograph on Ascutney Mountain, Vermont, and in 

 completing some work on the Porphyritic Gneiss formation of 

 New Hampshire. Mr. C. F. Marbut investigated the microscopic 

 characters of some siliceous limestones and allied rocks. 



Field work in the Archaean Highlands of New Jersey in connec- 

 tion with the United States Geological Survey has been carried on 

 by Professor Wolff in the summer, and during the winter consider- 

 able time was devoted to the preparation of a joint Monograph on 

 the Crazy Mountains, Montana, in collaboration with Mr. Walter 

 H. Weed. 



The subjects of Mineralogy and Petrography, of which the 

 former has been placed under Chemistry and the latter under 

 Geology, were in June united to form a new department of in- 

 struction, named the " Department of Mineralogy and Petrogra- 

 phy," and placed in the Division of Natural History. This union 

 of two closely connected subjects will prove a great advantage 

 both as regards instruction and investigation and economy of 

 resources. The two chemical laboratories belonging to each sepa- 

 rately have thus been united into one in the Mineralogical Section 

 of the Museum, and an excellent laboratory for mineral and rock 

 analysis will thus result. In the same way, a joint library has 

 been formed by uniting the two previously separate partial libra- 

 ries, and the collections and apparatus will be used to better 

 advantage. 



