16 ALASKAN MINEKAL RESOURCES IN 1906. 
SEWAKD PENINSULA. 
F. H. Moffit, assisted by P. S. Smith, completed the areal map- 
ping of the Nome and Grand Central quadrangles. This work is the 
first attempt to make an exhaustive study of the geology of any of 
the placer districts. It is hoped that as a result of such investiga- 
tions general laws for the occurrence and distribution of the placer 
gold of the peninsula may be formulated. Mr. Moffit presents a 
brief abstract of his conclusions on pages 126-145 of this report. 
Mr. Smith, in addition to his work with Mr. Moffit, made a recon- 
naissance of some of the other placer districts of the peninsula, a 
both to gather data on the progress of mining and also to familiarize 
himself with some of the larger problems of the province. 
Most placer mining is directly dependent on a supply of water; 
therefore a knowledge of the water supply is of first importance to 
this industry. The accurate determination of the mean discharge of 
any given stream must be based on observations extending through 
a long period of years to equalize the variations caused by abnormal 
seasons. Such an investigation was inaugurated at Nome during 
the last season. The area investigated embraced a belt of country 
about 20 miles wide, stretching inland from Nome to the Kigluaik 
Mountains, a distance of about 40 miles, and was chosen both 
because of its commercial importance and because the detailed maps 
were available for calculating the areas of stream basins. It is 
hoped that funds may be available to continue this work and to 
extend it to other parts of Alaska. 
These hydrographic surveys were made possible only through the 
cooperation of the water resources branch, which detailed John C. 
Hoyt, an experienced engineer, to take charge. Mr. Hoyt spent 
about two months in the field, and the observations were continued 
by his assistant, F. F. Henshaw. A brief summary of results will 
be found on pages 182-186. The complete report has already been 
published. 6 
YUKON DISTRICT. 
L. M. Prindle, assisted by C. S. Blair, made a geologic reconnais- 
sance southwest of the lower Tanana, covering about 2,000 square 
miles. The Kantishna placer district and a part of the Bonnifield, 
as well as the Cantwell coal field, were embraced within the scope of 
the investigation. 
E. M. Kindle, assisted by V. H. Barnett, made a careful study of 
the stratigraphy of the Paleozoic rocks of the upper Yukon basin. I 
In the course of this work he ascended Porcupine River as far as the 
international boundary. This investigation has an important bear- 
's See pp. 146-163. 
& Water supply of Nome region, Seward Peninsula, 1906: Water-Sup. and Irr. Paper No. 196, U. S. 
Geol. Survey. 
