Reviews 



Geology of the Nome and Grand Central Quadrangles, Alaska. By 

 Fred H. Moffit. Bull. U.S. Geol. Surv. No. 533, 1913. 

 Pp. 136. 



The Nome and Grand Central quadrangles are situated in the south- 

 central part of Seward Peninsula in an area included between 165° and i65°3o' 

 west longitude and 64°25' and 64°S7' north latitude. The Tigaraha schist 

 which is the uppermost member of the Kigluaik group (early Paleozoic and 

 possibly in part pre-Paleozoic) is the oldest formation exposed. One principal 

 granite mass and smaller dikes and sills intrude this schist. The relation 

 between the Tigaraha schist and the overlying Nome group appears to be one 

 of conformity. The Nome group (probably middle Paleozoic) makes up the 

 greater part of the mapped area. It consists of two schist horizons with an 

 intervening limestone formation. These beds are cut by greenstone dikes 

 and sills and to a small extent by granite. Quaternary (possibly including 

 some Tertiary) deposits that consist of marine and fluvial sands and gravels 

 and glacial debris succeed the Nome group. The mineral wealth of the Nome 

 district lies in its placer deposits. The richest of these are rapidly decreasing, 

 so that the present production can be maintained only by new and better 

 methods. The placers are described as residual, stream, beach, and gravel 

 plain. Dredging will play an important role in the future development. A 

 historic outline of the Nome placer development is given. There are gold, 

 stibnite, bismuth, scheelite, copper, and graphite lodes, but these are at pres- 

 ent not of commercial importance. 



V. O. T. 



Coastal Glaciers of Prince William Sound and Kenai Peninsula, 

 Alaska. By U. S. Grant and D. F. Higgins. Bull. U.S. 

 Geol. Surv. No. 526, 1913. Pp. 72. 



The aim of this report is to "supply some definite information regarding 

 the present positions of the fronts of the glaciers" of Prince William Sound 

 and Kenai Peninsula and "the more evident facts of their fluctuations." The 

 Barry, Surprise, Chenega, Princeton, and Holgate glaciers have retreated from 

 one to two miles within from 10 to 50 years or more. Since the growth of the 

 present coniferous forest, the Columbia and Bainbridge glaciers have recently 

 advanced to their maximum positions. The glaciers on the west side of 

 College Fiord and Harvard Glacier have been advancing for the past ten years; 

 their maximum advance was in 1905. Many of the glaciers have exhibited 

 alternate advances and retreats of notable extent. There is no indication of a 

 general advance or retreat during the last 50 years. These glaciers are rem- 

 nants of an ice sheet whose upper surface once reached an elevation of 2,000 

 feet at the main coast line. The accompanying photographs (that constitute 

 40 plates) of the glaciers are exceedingly good and instructive. 



V. O. T. 

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