242 Scientific Intelligence. 



This volume, edited by the State geologist, Prof. Alfred C. Lane, 

 contains the results reached by Dr. Ries in examining the clays 

 of Michigan. An account is given of the various localities and 

 also of the tests to which the clays irom them have been subjected. 



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 V 4. The Geological and Natural History Survey of 3Iinnesota. 

 The Twenty-fourth (and filial) Annual Report for the years 

 1895-1898. N. H. Winchell, State Geologist. 1899. Pp. 1- 

 284. — The main body of this report consists of lists and notes of 

 rock samples, record of the field work, and indices, but the intro- 

 ductory statement by the State Geologist is of special interest. 

 A brief review of the history of the Survey during its 27 years is 

 given. The Salt Spring lands of the State were early set apart 

 to be used for the prosecution of the Survey. The State Geol- 

 ogist estimates that through the agency of the State Geologist, 

 indemnity lands to the amount of 19,872 acres were discovered; 

 these were transferred by the Legislature of 1885 to the Board 

 of Regents for the purpose of a Geological and Natural History 

 Survey. The Geological Survey of Minnesota has therefore been 

 endowed by grants of land, 18,771 acres of the Salt Spring lands 

 and 19,872 acres in 1885, making a total of 38,643 acres. 



The total cost of the Survey from 1872 to July 31, 1899, is 

 estimated to be $146,357.27. "The total revenue to the State as 

 shown in dollars that can be counted, in excess of the public good 

 that may come from the Survey," is claimed to be $132,609.26. 



The State Geologist is to be congratulated that he can make so 

 good a showing for his administration of the Survey of his State. 



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5. The Pleistocene Geology of the South Central Sierra Nevada 

 vnth Especial Reference to the Origin of Yosemite Valley; by 

 Henry Ward Turner. — Proceedings of the California Academy 

 of Sciences, 3d Series, Vol. i, No. 9, pp. 262-321, with 9 plates.— 

 As an introduction to the discussion of the origin of Yosemite 

 Valley, Mr. Turner reviews the orogenic movements of the Sierra 

 Nevada region and describes three pleistocene periods, Sierran, 

 Glacial and Recent. There is no common opinion regarding the 

 importance of glacial work in the formation of the valleys of the 

 Sierras. John Muir ascribes the topography of the entire moun- 

 tain system from base to summit to the work of glacial ice. Prof. 

 Whitney doubted the existence of any glaciation in the region. 

 Other writers have held intermediate positions. Because of this 

 wide variation in opinion, Turner has critically reexamined the 

 evidence regarding the erosive power of ice, the origin of rock 

 basins and glacial cirques with special reference to the Sierras. 

 He concludes that "the theory that great canyons or even con- 

 siderable ravines are formed by the gouging action of ice does 

 not seem supported by the evidence," and that ice erosion has not 

 been a controlling factor in the formation of Yosemite. That this 

 valley is the result of a drop fault was held by Whitney, Reyer 

 and Russell. The rocks, however, in general show no faulting 



