ABSTRACTS OF PAPERS 117 



on leached till, whereas in the Belvidere area, where the auger penetrated till 

 beneath calcareous loess, the till was calcareous. In places a soil zone sepa- 

 rates the loess and underlying till in the area which I have mapped as Illi- 

 noisan, but not in the Belvidere lobe ; likewise an old loess, like clay, separates 

 the relatively fresh loess from the underlying till in the former area, but not 

 in the latter. These stratigraphic relations of loess and till seem to me to be 

 fundamentally important in distinguishing the two areas. The boundary be- 

 tween the two areas is different from that appearing in Monograph XXXVIII. 

 As for the average depth of leaching which I cited, the depths found do not 

 have a uniform range from to 8 feet, giving an average of 4, but the great 

 majority are around 4 feet. This will be brought out in my more detailed 

 report, but the average depth was emphasized for me — the process of field- 

 work by the fact that calcareous till in the Belvidere lobe was encountered 

 either just at the depth of the first auger section of 3% feet or just after 

 adding the second section. 



LATE PLEISTOCENE HISTORY OF THE LOWER MOHAWK AND MIDDLE 



HUDSON REGION 



BY JAMES H. STOLLER 



( Abstract ) 



Some additional data gathered in recent field-work seem to afford a clear 

 explanation of the drainage history of the region, concerning certain features 

 of which divergent views have previously been held, and also have a bearing 

 on the more general problems of the Pleistocene history of the Hudson-Cham- 

 plain Valley. The key to the drainage history and the resulting physiographic 

 features is found in the repeated shifting of the course of the Iroquois-Mohawk 

 River, as its flooded and sediment-bearing waters flowed across an area from 

 which the static waters of the Mohawk-Hudson region were receding. The 

 origin of Saratoga Lake and of Round Lake, of the "old channel of the Hudson 

 west of Schuylerville," of the inlet of the Hudson River at Coveville, and of 

 other features, is considered. 



Presented by title in the absence of the author. 



ABLATIO N OF THE EASTERN LOBE OF THE WISCONSIN ICE-SHEET 



BY JOHN H. COOK 1 



(Abstract) 



By the term "eastern lobe" is designated all that body of glacial ice forced 

 southward beyond the mountain barriers of northern New York, Vermont, New 

 Hampshire, and Maine and lying east of the lobe which spread south and 

 southeast from the Ontario basin. Within this area the influence of larger 

 and smaller masses of stagnant ice in shaping the existing topography has 

 been widely recognized and the evidences of continued movement of the lobe 

 during the period of "recession" have been found to be meager. The frontal 



1 Introduced by John M. Clarke. 



