234 THE POPULAR SCIENCE MONTHLY. 



seeks the lowest levels attainable, these currents will find a place at 

 the bottom of the ice-sheet, and wear away the ground-moraines and 

 other debris. Hence banks of earth or clay will be found continuous 

 from the ice-cliff to as great a distance toward deep water as the 

 currents have power to transport the material. Marine animals live 

 in and upon these banks, and leave their remains in them. Hence the 

 deposit is analogous to that series of marine clays called Champlain 

 by me in 1861, and occurring so plentifully up to three hundred feet 

 in the St. Lawrence Valley, and to one hundred and sixty feet along 

 the coast of northern New England and the Provinces. It is obvious 

 that they were contemporaneous with the glacial moraines upon the 

 land, and not entirely consecutive, as so many have supposed. This 

 was the position assumed by the late Professor Agassiz, and confirmed 

 by our own published observations in the " Geology of New Hamp- 

 shire," describing the occurrence of fossiliferous beds between the 

 lower and upper till of Portland, Maine. 



The Eastern American Ice Area. The latest generalizations 

 indicate that some part of the Labrador Peninsula may be considered 

 as the center from which the ice has radiated over the Dominion of 

 Canada and the northern United States east of the Rocky Mountains. 

 By regarding the Greenland and polar areas as independent of the 

 Labrador sheet, though possibly confluent at the time of maximum 

 glaciation, a multitude of difficulties are removed, and our American 

 glaciers are seen to have been subjected to the same laws as the several 

 ice-fields of other parts of the world. This area extends from Baffin's 

 Bay to Dakota, and from Hudson's Bay, or the Arctic Archipelago, to 

 a line drawn from the Great Banks of Newfoundland through New 

 Jersey, southern Ohio, etc., to the plains east of the Rocky Moun- 

 tains. 



Most of this territory exhibits a southwesterly course of glaciation. 

 This is well shown over the highlands between Hudson's Bay and the 

 St. Lawrence Valley, the valley itself, western New York, Ohio, Iowa, 

 Minnesota, Manitoba, and so on to the extreme western limits. It is 

 very prominent from Lake Superior, near the international boundary, 

 westwaivd to the Rocky Mountains. In eastern New York and the 

 Champlain and Hudson Valleys the course is southerly. In New Eng- 

 land the dominant direction is southeasterly, and the same is true of 

 New Brunswick and Nova Scotia. The exceptional deviations are due 

 to local influences, exerted in the decline of the age. The facts in 

 hand for Newfoundland are too few for a satisfactory delineation, 

 while not in disagreement with these generalizations. On the east 

 coast of Labrador there arc several fiords, as if there had been an ice- 

 sheet upon the upper part of the peninsula, moving northeast and east. 

 Professor O. M. Lieber'e sketches in the Coast Survey report suggest 

 a local glaciation, and not such a general smoothing as would be man- 

 ifested in cast' the ice had come from the opposite Greenland coast. 



