7 



REPORT ON THE GEOLOGICAL DEPARTMENT. 



By J. D. Whitney, Sturgis-Hooper Professor. 



At the close of the preceding year the Sturgis-Hooper Professor 

 was engaged in passing through the press Part L of No. 2 of 

 Yol. YIL of the Memoirs of the Museum, the same being the 

 introduction to a general discussion of the climatic changes of 

 later geological times, and containing that portion of the work 

 which especially relates to the glacial and surface geology of the 

 Cordilleras of North America. The remainder of this contribu- 

 tion to geological science is now in press, and will be issued 

 without further delay. This will complete Yol. YH. of the 

 Memoirs. 



The following papers have been published during the past year, 

 giving the results of work done in the Lithological department. 



By Dr. Wadsworth, Assistant in Lithology. 



1. On the Origin of the Iron Ores of the Marquette District, Lake 

 Superior. Proc. Bost. Soc. Nat. Hist, 1880, XX. 470-479 ; Eng. and 

 Min. Jour., 1881, XXXII. 286. 



2. On the Age of the Copper-bearing Rocks of Lake Superior. Proc. 

 Am. Assoc. Adv. Sci., 1880, XXIX. 429-430 ; Eng. and Min. Jour., 1881, 

 XXXIL 270. 



3. The Yolcanic Dust from Dominica. Nature, 1880, XX. 266, 

 267. 



4. A Microscopical Examination of some Tufas from Florissant, Col- 

 orado. Bull. U. S. Geol. Survey, YL 1881, pp. 286, 287. 



5. On an Occurrence of Gold in Maine. Bull. Mus. Comp. Zool., 1881, 

 Geol. Ser. I. 183. 



6. A Microscopical Study of the Iron Ore or Peridotite of Iron Mine 

 Hill, Cumberland, R. I. Ibid., pp. 183-187; Proc. Bost. Soc. Nat. 

 Hist., XXL 1881. 



7. A Microscopical Examination of the Mt. Ktaadn Granites. Bull. 

 Mus. Comp. Zool. 1881, Geol. Ser. L 209, 210. 



