RE VI J:: IV S ' 303. 



geology, is worthy of special note as one of the signs of the educa- 

 tional times. It is significant both as an indication of a demand and 

 as exemplifying a supply. It is a gratifying mark of progress that 

 there should have grown to be a place for a work of this character as 

 a supplement to the usual treatises on geography and geology. It is 

 a not less gratifying mark of progress that such a demand should be 

 appreciated and met by a careful and competent scientist of high 

 position. 



The work opens with a clear and brief statement of the nature of 

 glaciers, and of their varieties and of the work done by them. Their 

 distribution in North America is then sketched comprehensively, after 

 which individual glaciers and glacial districts are described in detail. 

 It is in the study of these glaciers individually, aided by the numerous 

 photographic illustrations, that the real characters of glaciers will come 

 to be realized by the students. The average reader will doubtless be 

 surprised at the number, variety and instructiveness of American 

 glaciers. They very greatly surpass those of all other accessible conti- 

 nents. 



Following the individual descriptions are chapters on the climatic 

 changes indicated by the glaciers of North America, upon the cause 

 and mode of glacial motion, and upon the life history of a glacier. 

 The discussions of theoretical questions are conservative and judicial 

 in tone, and manifest a notable tendency to eclectic conclusions. Pro- 

 fessor Russell's comprehensive statement of the various hypotheses of 

 glacial motion will doubtless be found one of the most interesting 

 sections of the volume by advanced glacial students. The work is 

 heartilv commended to teachers and general readers as well as students. 



T. C. C. 



Former Extoision of Cornell Glacier near the SoJithern end of Melville 

 Bay. By Ralph S. Tarr. Bull. Geol. See. Amer., Vol 

 VIII, pp. 251-268. Plates XXV to XXIX, March 1897. 

 An abstract of this paper was given in the January-February num- 

 ber of this Journal, pp. 95-96. An editorial relative to it appeared 

 in the same number, pp. Si-85. C(5mmunications in reference to it 

 have also appeared in Science, Vol. V, No. 113, February 26, p. 344; 

 No. 114, March 5, pp. 400-401, and No. 117, March 26, pp. 515-516. 

 This further notice is introduced mainly for the purpose of presenting 



