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by the Variation of the Surface Tension of Liquids," "The Depths and 

 Submarine Features of the North Polar Basin, with chemical Analyses 

 and Microscopical Composition of the Deep Sea Deposits," " Diato- 

 maceae and Algae living on the Drifting Ice and in the Sea of the 

 North Polar Basin." Many other memoirs are announced for still 

 later volumes. It is stated that the number of volumes will probably 

 be five or six, which it is hoped may be finished in the course of about 

 two years. These volumes will not only furnish a large body of infor- 

 mation about a little-known region, but some of them will deal with 

 questions of world-wide application. The reports are to be issued in 

 the English language only. 



R. D. S. 



The Pleistocene Geology of the South Central Sierra Nevada, with 

 especial reference to the Origin of the Yosemite Valley. By 

 Henry Ward Turner. Proceedings of the California Acad- 

 emy of Sciences. Third Series, Vol. I, No. 9; 9 Plates; 

 pp. 361-321. 

 This paper gives a brief outline of the pre-Pleistocene orogenic 

 history of the Sierra Nevada, the orogenic movements of the Pleisto- 

 cene, and a brief sketch of the Pleistocene history of the region, as an 

 introduction to the discussion of the origin of the Yosemite Valley. 

 The Sierran period, the period of high lands preceding glaciation, is 

 included in the Pleistocene. Some brief notes on the glacial period 

 are also given, and the conclusion reached that there were two periods 

 of glaciation separated by an interval of deglaciation, though the evi- 

 dence on this point is not looked upon as altogether conclusive. The 

 assumption that in the interior of the continent there were two (and 

 not more) well-marked glacial epochs, needs to be modified in the light 

 of the investigations of the last few years. The brief statement con- 

 cerning the cause of the glacial period, also seems not to take account 

 of the latest and most satisfactory views on this subject. 



The several hypotheses which have been advanced concerning the 

 origin of the Yosemite are considered, and the conclusion reached that 

 this valley was not scooped out by the ice (Muir); that it is not a river- 

 cut canyon, the walls of which were made vertical by the sapping action 

 of ice (Johnson); and that there is no adequate evidence that it is due to 

 a drop fault (Whitney, et. a/.); but that it owes its origin to river 



