Reviews 



Upper White River District, Yukon. By D. D. Cairnes. Geol. 

 Survey Canada, Memoir 50, 1915. Pp. 191, figs. 2, pis. 17, 

 maps 3. 



This report covers an area of about 800 square miles lying along the 

 Alaska- Yukon International Boundary from latitude 6i° 40' to 62 30'. 

 It is considered to be a promising area for mineral deposits of economic 

 value. 



The oldest rocks exposed are mica schists referred to the Yukon 

 group of pre-Cambrian age. Upon these rest 1,500 feet of Carbonifer- 

 ous limestones and elastics followed by 1,000 feet of Mesozoic shales 

 and sandstones. At a few points Tertiary beds were observed. These 

 beds are in part flat-lying, and in part have been highly dynamically 

 metamorphosed. 



The writer believes that the Nutzotin Mountains are due to differ- 

 ential erosion rather than to faulting. They remained as a region of 

 considerable relief at the time of the peneplanation of the Yukon plateau 

 region and were further uplifted between the late Miocene and the early 

 Pleistocene. A different explanation from that suggested by geologists 

 of the United States Geological Survey is advanced to account for 

 drainage changes along White River. 



W. B. W. 



Wyoming and McDowell Counties. By R. V. Hennen. West 

 Virginia Geol. Survey, 1915. Pp. 783, pis. 31, figs. 28, maps 2. 



McDowell County, situated on the southern border of the state, has 

 led all the counties in the state in coal production since 1905. Approxi- 

 mately 15,000,000 tons were produced in 1915, and at this rate its avail- 

 able coal will last about two hundred and fifty years. Wyoming County 

 coal fields have not been developed until recently, but its coal reserves 

 equal those of McDowell County. 



The Pottsville series has a remarkable development here. It 

 increases from a thickness of 250 feet at the northern edge of the state 

 to a maximum of 3,850 feet in these counties. It has been differentiated 

 into three groups and two score formations. 



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