GLACIAL GEOLOGY OF THE COHOES QUADRANGLE I7 



THE LAKE ALBANY DEPOSITS 



The body of glacial waters in which the stratified clays of the 

 upper Hudson valley were deposited was named by Woodworth 

 Lake Albany. He limited the extent of Lake Albany to the waters 

 represented by the deposits extending from near Rhinebeck on the 

 south to the Fort Edward district on the north^ (north of the Cohoes 

 quadrangle). In his view, the gathering of the waters of Lake 

 Albany was pari passu with the melting of the ice sheet in its retreat 

 northward in the middle Hudson valley. 



Another view is that the deposits are ebiuarine, having been laid 

 down in the sea-level waters v/hich extended as an inlet up the 

 Hudson valley from the ocean at New York.^ 



Fairchild has stated the conclusion that the body of waters in 

 which the Hudson valley clays and sands were deposited was at 

 sea level and at its highest development formed a strait connecting 

 the oceanic waters which then occupied the St Lawrence valley 

 with the ocean at New York. "As the ice front melted back the 

 ocean followed it and flooded the valley. The waters were at first 

 the Hudson inlet; later, the Hudson-Champlain inlet; and finally, 

 the Hudson-Champlain strait."^ 



In this report we shall refer to the waters as Lake Albany, 

 though without implication as to the correctness of the first men- 

 tioned of the above interpretations. We shall, however, below call 

 attention to certain facts of topography Wihich seem to afiford clear 

 proof that the body of waters in question subsided (that is, 

 dwindled to a river) while drainage from the great interior lakes 

 (Algonquin-Iroquois stage) was still through the Mohawk valley. 

 The inference is that Lake Albany disappeared prior to the opening 

 of the St Lawrence channel (as due to ice melting) ; that is to say, 

 prior to the invasion of marine waters in the St Lawrence basin. 



The writer would also state that in this report the term " sub- 

 sidence " is used as pertaining to the fact of the withdrawal of the 

 Lake Albany waters but without implication as to whether the 



' Ancient Water Levels. N. Y. State Mus. Bui. 84, p. 177 and 242, 1905. 



* Merrill, Quaternary Geology of the Hudson River Valley. loth 

 Annual Rep't of the State Geol., 1890. Peet, Glacial and Postglacial 

 History of the Hudson and Champlain Valleys. Journ'al of Geol., 12:640. 

 1904. This author considers two alternation' hypotheses: (i) the water 

 body was a lake made by. a barrier at the south, (2) the water body 

 was an arm of the sea. 



'Fairchild. Ann. Rep't of N. Y. State Geol. 1912, p. 24. 



