abstracts: geology 21 



clines. The axis of this great trough or syndinorium trends generally 

 northeast and southwest. The general dip of the rocks in Wayne 

 County is toward the southeast and amounts to about 20 feet to the mile. 

 There is, however, considerable difference in the degree and direction 

 of dip from place to place, due partly perhaps to unconformities in 

 the rocks of the different series and systems and to unequal deposi- 

 tion of sediments, but mainly to warping in the process of folding, 

 which caused the minor folds and wrinkles that seem to be so inti- 

 mately associated with the origin of the oil pools. 



Alfred H. Brooks. 



GEOLOGY.— r/ie Iditarod-Riiby region, Alaska. H. M. Eakin. U. S. 

 Geological Survey Bulletin No. 578. Pp. 45. 1914. 



The province treated extends from Yukon River at Ruby to Idita- 

 rod River and includes the Ruby, Innoko, and Iditarod mining districts. 

 The hard rocks of the Ruby district belong to an older complex of 

 more or less altered sedimentary and volcanic rocks which can be pro- 

 visionally correlated with the metamorphic Paleozoic and possibly 

 older rocks of the Yukon-Tanana region. The Innoko and Iditarod 

 districts are underlain by a younger series, predominantly of sedi- 

 mentary and subordinately of volcanic rocks, in part at least of Cre- 

 taceous and probably all of Mesozoic age. Intrusive rocks occur in all 

 the districts. They include granitic batholiths, stocks, dikes and sills, 

 that range widely in lithologic character. In most of the region 

 the hard rocks are heavily mantled by alluvial and possibly lacustrine 

 deposits in the lowlands, by residual clays and fragmental deposits on 

 the slopes and lower ridges, and locally near the higher mountain 

 groups by morainic and glacial out wash deposits. 



Auriferous deposits occur in both the Paleozoic and Mesozoic areas, 

 and they are probably related genetically to certain of the younger 

 intrusive rocks. This relation is especially clear in the cases of the 

 monzonites of the Iditarod district and the altered rhyolite porphyry 

 dikes of the Innoko district. H. M, E. 



GEOLOGY. — The ore deposits of northeastern V/ashington. Howland 

 Bancroft; including a section on the Republic mining district. 

 Waldemar Lindgren and Rowland Bancroft. U. S. Geologi- 

 cal Survey Bulletin No. 550. Pp. 215. 1914. 

 The area investigated in the reconnaissance whose results are here 



set forth is situated in the extreme northeastern part of the State of 



