430 Reviews — Geological Survey of United States. 



(2) TJnited States of America. — The geology of Alaska is the 

 subject of a brief review in a previous number of this journal (Geol. 

 Mag., 1914, p. 31), in which six bulletins relating to this territory- 

 were noticed. Since then we have received three additional bulletins, 

 ISTos. 536, 538, and 542, dealing with the geology of parts of Alaska. 



No. 536. The Noatak-Kobuk Region, Alaska. By Philip S. Smith, 

 1913. — This deals with the geology of the basins of the Kobuk and 

 Noatak Rivers, which drain into Kotzebue Sound. The shores of 

 this part of Alaska were visited by Sir John Franklin in 1826 and by 

 many other Arctic explorers. Having regard to the great difficulty 

 of exploration in this country, the maps produced are extraordinarily 

 complete. Large areas still remain unexplored, but food and fuel are 

 scarce and there seems small prospect of developing any mineral 

 occurrences. A large area is occupied by metamorphosed sediments, 

 possibly Palaeozoic, and by Palaeozoic limestones, including some beds 

 of Silurian and Devonian age. Carboniferous sandstones and lime- 

 stones have yielded fossils of Mississippian age. The igneous rocks 

 include altered basalts, in part contemporaneous with Palaeozoic 

 limestones; rocks of andesitic and dioritic composition are associated 

 with Lower Cretaceous or Jurassic rocks, and are cut by granitic 

 intrusions and basaltic rocks of late Tertiary age. 



No. 538. A Geological Reconnaissance of the Circle Quadrangle, 

 Alaska. By L. M. Prindle, 1913. — The area mapped is situated in 

 the Yukon-Tanana region. Here again there are large areas of 

 Palaeozoic sediments, those of pre-Ordovician age being highly 

 metamorphosed. Jurassic and Triassic rocks appear to be absent. 

 Diabase and basalt are associated with the Palaeozoic rock, and there 

 are large intrusions of biotite-granite of Mesozoic age. The youngest 

 igneous rocks are late Cretaceous or early Tertiary, and consist of 

 rhyolites, dacites, and basalts. 



No. 542. Mineral Resources of Alaska : Report of Progress of 

 Investigations in 1912. By A. H. Brooks and others, 1913. — This 

 is the ninth of a series of bulletins giving preliminary reports on 

 deposits of economic interest and a summary of the mining industry 

 in 1912. 



The "Bibliography of North American Geology of 1912, with subject 

 index", by John M. Nickles, 1913 (Bulletin 545), includes all 

 publications bearing on the geology of North America and the 

 adjoining islands, also of Panama and the Hawaiian Islands. It follows 

 the plan of similar bibliographies published annually since 1906. 



Other bulletins received are Nos. 531 and 539, both of which are 

 restricted to information having a purely economic bearing. 



(3) Alabama Geological Survey. — "We have received Bulletins 

 13 and 14, being the statistics of the mineral production of Alabama 

 for 1911 and 1912, compiled from the Mineral Resources of the United 

 States, by C. A. Abele. The Geological Survey has also issued a third 

 edition of Iron Making m Alabama, by Dr. W. B. Phillips, the earlier 

 editions of which were published in 1896 and 1898. 



