REVIEWS 465 



of the process that was much more intense during the later stages 

 of the earth's growth. Cosmic accretions, which may be a notable 

 factor, would be equally functions of either hypothesis so far as the 

 maintenance of the atmosphere and ocean is concerned. 



In submitting the newer hypothesis to the test of physical princi- 

 ples and mathematical computations, Fisher has done it an honor that 

 is sincerely appreciated. By showing that its more radical features lie 

 within the tenable limits of theory, he has helped to give it a place as 

 a genuine working hypothesis ; and as such it may have some stimu- 

 lating value as a competitor of the gaseous and molten theory which 

 has practically monopolized geological opinion for the past century. 



T. C. C. 



Glacial Sculpture of the Bighorn Mountains, Wyoming. By Francois 

 E. Matthes. Extract from the Twenty-first Annual Report 

 of the United States Geological Survey, 1899-1900. Wash- 

 ington, 1900. 



Glaciation affected the crest of the Bighorn Mountains for more 

 than thirty miles. The range was not covered by a continuous ice 

 cap, and glaciation was confined to valleys. The mountains abound in 

 well developed, elongate, valley-like cirques, which have been but little 

 altered by postglacial changes. The author indorses Johnson's view 

 of the origin of cirques, namely, that they are due to sharply localized 

 and abnormally vigorous weathering, by rapid alternation of freezing 

 and thawing at the exposed bottoms of bergschrunds. Mr. Matthes' 

 studies have led him to the conclusion that the location of the berg- 

 schrunds in any valley is determined by the depth of the neve. 



The longest glacier of the Bighorn Mountains is said to have been 

 eighteen miles in length, its terminus reaching down to an altitude of 

 less than 7000 feet. The thickness of the larger glaciers was 1000 

 to 1500 feet. Small glaciers still exist in the highest part of the 

 range, a little below 44° 30', at an altitude of about 12,000 feet. 



In addition to the account of the effects of the active valley glaciers 

 on topography, the author discusses the effect of inactive snow and 

 neve. The neve effects are described under the term "nivation," and 

 the "nivated" valleys are distinguished from the glaciated valleys. 

 This, so far as we are aware, is the first attempt to analyze the effects 

 of inactive ice and neve on topography. The discussion even involves 



