754 General Notes. [September, 



in all such formations. The majestic proportions of the great 

 Been in the fact that it advanced as far south 



upon the mountains as in the valleys; for example, the valley be- : 

 tween the Kittatiuny and Pocono mountains.though twenty miles 

 wide and one thousand feet deep, caused but a slight deflection of 

 the ice-front to the south. The same is true where the moraine 

 crosses the valley of the east branch of the Susquehanna. The 

 grand deflection of the line to the northward is evidently due to 

 variations in the forces which were pushing from behind. Now 

 that an accurate knowledge of the southern limits of the conti- 

 nental glacier is being obtained, it will be possible to get a variety 

 of approximate estimates of the quantity of erosion which has 

 taken place since the great ice age, and so a more correct idea of 

 its antiquity. Full accounts of this subject will appear in the 

 report of the Pennsylvania geological survey. Arrangements are 

 in progress for Mr. Wright to continue the exploration through 

 Ohio the present summer. 



New Phyllopod and Phyllocaridan Crustacea from the 

 Devonian of New York. — A very interesting species of Estheria 

 {E.pulcx) is described by J. M. Clarke in the American Journal 

 of Science. If this is a genuine Estheria (and it differs from other 

 species in wanting a straight hinge margin) it is the oldest 

 species of the genus yet found, though E. membranacea Jones, 

 occurred in the Old Red of Caithness. In this country no spe- 

 cies of Estheria has been found below the Trias. 



The other forms described by Mr. Clarke arc not true Phyllo- 

 pods, but should be referred to the order Phyllocarida, being 

 related to Discinocaris. They are forms of much interest. Spathio- 

 caris emersomi Clarke, gen' et sp. nov., is from the Portage of 

 Ontario county. The second form of this order, LisgocaQ 

 lutheri Clarke, gen. et sp. nov., is from the base of the Hamilton, 

 in the same horizon as Estheria pit! ex. The author refers it to 

 the " Apus type of the Phyllopods," but are they not more prop- 

 erly allied to Nebalia, the rostrum having been lost or separated 

 after death ? Only the carapace of this genus and of Spathwcatis 

 occured, the abdomen not having been discovered. 



White's Contributions to Mesozoic and Tertiary Pai.i.on- 

 tology.— Dr. C. A. White describes in the Proceedings of the U. 

 S. National Museum, several new mollusks from the Laramie and 

 Green River groups, which is succeeded by a short paper on the 

 molluscan fauna of the Truckee group, including a new form. 



In the American Journal of Science he discusses certain condi- 

 tions attending the geological descent of some North American 

 types of fresh-water, gill-bearing mollusks. Dr. White claims that 

 the rivers of North America having existed from early geologi- 

 cal times, that some of them becoming confluent, have dissemi- 

 nated molluscan forms. Thus the Ohio and Upper Mississippi, the 



