40() Review of Recent Geological Literature. 
Professor Raphael Pumpelly, in charge of the division of Archaean 
geology, has studied the structure of the Green mountains and of the 
Hoosac range and Graylock in northwestern Massachusetts. Prof. N. 
S. Shaler, of the Atlantic Coast division, was occupied in field-work on 
Martha’s Vineyard, Nantucket, and Mount Desert islands, and in the 
region of the Dismal Swamp in Virginia; and he contributes in this 
volume a memoir on the geology of Martha’s Vineyard. The work of 
Mr. G. K. Gilbert, of the Appalachian division, with his assistants, 
has been chiefty devoted to an investigation of the structure of the 
Appalachian mountain system in the states southwest of Pennsyl¬ 
vania. 
Professor R. D. Irving, of the Lake Superior division, reported field¬ 
work by himself and assistants in northern Michigan, Wisconsin, and 
Minnesota; and he presents in this volume a discussion of the classifi¬ 
cation of the early Cambrian and pre-Cambrian formations, which are 
so fully developed in that region. 
The work of the division of glacial geology, under Prof. T. C. Cham¬ 
berlin, has included various investigations across the entire northern 
belt of the United States, from Maine to Idaho and Washington. Pro¬ 
fessor Chamberlin has supplied to this report a very elaborate mono¬ 
graph on glacial striae, with a map showing their courses and the ex¬ 
tent of the glacial drift. 
Dr. F. V. Hayden, of the Montana division, reported work in the 
Gallatin valley and the Bridger range, including the coal beds which 
are profitably worked near the Boseman tunnel of the Northern 
Pacific railroad. Mr. Arnold Plague, of the Yellowstone Park division, 
has given special attention to the later of the more massive lava flows 
in that district, and to their relation to the so-called fossil forests and 
plant remains interbedded in the 2,000 feet of volcanic ashes, muds, and 
breccias found there. He concludes that volcanic activity in the Park 
probably continued, w r ith varying intensity and occasional periods of 
rest, throughout the greater part of the Tertiary and into Quaternary 
time. 
The Colorado division, under Mr. S. F. Emmons, worked in the 
Gunnison or Crested Butte region and in the Denver basin region, an 
area around Denver supposed to be underlaid by coah The structure 
has proved exceedingly complicated, even beyond expectation. Mr. 
George F. Becker, of the California division, reports the completion of 
his field studies of the quicksilver deposits of Steamboat springs, Ne¬ 
vada, and the beginning of work on the Gold Belt, which will form 
the next subject of investigation by that division. 
Capt. C. E. Dutton, assisted by Mr. J. S. Diller, has studied the 
Cascade mountains and the coast ranges of the Pacific states. He 
finds that volcanic action probably prevailed there during nearly the 
whole of the Tertiary era. 
Mr. Lawrence C. Johnson, of the Louisiana division, reports an ex¬ 
amination of the iron deposits of that state. Mr. W. J. McGee, of the 
