abstracts: geology 633 



GEOLOGY. — Mining and mineral deposits in the Cook Inlet-Susitna 

 region, Alaska. Stephen R. Capps, J. B. Mertie, Jr., and G. C. 

 Martin. U. S. Geol. Survey, Bull. 692-D. Pp. 106 (177-282), 

 pis. 3, figs. 4. 1919. 



Contents : 



1. Gold lode mining in the Willow Creek district. Stephen R. Capps. 



2. Mineral resources of the western Talkeetna Mountains. Stephen 

 R. Capps. 



3. Mineral resources of the upper Chulitna region. Stephen R. 

 Capps. 



4. Platinum-hearing gold placers of the Kahiltna Valley. J. B. 

 Mertie, Jr. 



5. Chromite deposits in Alaska. J. B. Mertie, Jr. 



6. Geologic problems at the Matanuska coal mines. G. C. Martin. 



1. Quartz lodes in the Willow Creek district, Alaska, where mining 

 has been done since 1908, have yielded more than $1,600,000 in gold 

 and silver and are still being worked profitably. The character of the 

 deposits and the work done in the district in 191 7 are described. 



2. The western Talkeetna Mountains have long been considered a 

 promising field for the prospector, but the only productive part of it 

 thus far is the Willow Creek district. The construction of lines of 

 Government railroads to the region has made information concerning 

 the region especially timely and valuable. A sketch map of the region 

 is given and its geography and geology as well as the vegetation, game, 

 and routes of travel, are described. 



3. The mineral prospects in the upper Chulitna region lie 15 to 30 

 miles southwest of Broad Pass and include both gold lodes and gold 

 placers. For several yearg work has been done on lode claims in this 

 remote region, which will be made more easily accessible by the Gov- 

 ernment railroads. The bulletin includes a sketch map of the region 

 and a description of its geography, geology, vegetation, and game 

 animals, and details of the claims and prospects. 



4. Mr. Mertie gives a geologic sketch map of the Kahiltna Valley, 

 describes its geography and geology, and presents an account of its 

 mineral resources, which includes descriptions of the placers on many 

 creeks. Though gold is the only mineral thus far recovered in com- 

 mercial quantities the placers have yielded small quantities of other 

 valuable minerals, which include platinum and ores of tin and tungsten. 



5. The chromite deposits of present interest in Alaska are at the 



