1 882.] Geology and Paleontology. 1029 



moraine barrier lakes, which are now found on Pike's peak, and 

 in the Alps and the north-and-south lakes in Central New York, 

 such as Cayuga, there are many others " whose obstruction must 

 be given the more general name of glacial or fluviatile drift." 

 Farther on he says : " The detritus of the glacial period was de- 

 posited with much irregularity, and it must often have interrupted 

 the drainage lines of pre-glacial times ; we cannot doubt that the 

 greater number of lakes in Canada, New England and the Adi- 

 rondack's, are of this origin, but nowhere are drift barriers of 

 more significance than in the region of our great lakes." Davis 

 believes that the evidence ordinarily quoted to prove their glacial 

 origin proves only their glacial occupation. He regards Lake 

 Erie as the effect of simple subaerial erosion slightly modified by 

 glacial action, while he does not feel obliged to regard the other 

 great lakes as the "work of the great ice-plow." He considers 

 St. Mary's river, Niagara and the St. Lawrence to be "all post- 

 glacial overflows after the obstruction by drift and the change of 

 level by northern depression were accomplished." The brief dis- 

 cussion is of a good deal of value, and will be read with interest 



sors Newberry, Lesley, Spencer and other of our geologists. 



fully equal to \i not superior to its predecessors In interest and 

 value, both from a practical and scientific point of view. Mr, T. 

 H. Johnson's report on the transverse strength and elasticity of 

 building stones is valuable and graphically 'illustrated, and Pro- 

 fessor Collett, the State geologist, has been efficiently aided in his 

 work by Messrs, R. T. Brown, M. N. El rod, A. J. Phinney and 

 John N. Hurty. The volume is Largely made up of palaeonto- 

 logical matter supplied bv Professor James Hall and Dr. C. A 

 White, being illustrated with fi ft v- five plates, rendering the vol- 

 ume of much educational value.' 



Two new Genera of Mammalia from the Wasatch Eocene. 

 —The Phenacodus laticuneus differs from the species of Plunaco- 

 dus in the form of its superior premolars. The second, possesses 

 two cusps while there is but one in the -onus Phcu.icodus. The new 

 genus may be called Diacodexis. The species referred by me 



molar, and general dental characters, they agree with Loplnodon, 

 veloped'. The genus may be called llcptodon, the type is Lophic- 



eport, by Dr. C. A. White, printed as 



ling volume of the Wheeler Survey 



The collection described represents 



