634 PROCEEDINGS OF THE BALTIMORE MEETING 



poured the land and glacial drainage of the time, with consequent elevated 

 deltas. The Schoharie lake had outlets to the Hudson and the Delaware, and 

 subsequently the Mohawk waters overflowed southwestward to the Susque- 

 hanna, but finally to the Hudson. 



The earliest outlet of the Mohawk Valley waters seems to have been by the 

 col at the head of the Otsego-Susquehanna valley, with elevation somewhat 

 under 1,400 feet. A lower escape was found by the Unadilla valley, at about 

 1,220 feet, and possibly by the Chenango valley at 1,150 feet. Later the out- 

 flow was eastward to the Hudson by Delanson and Altamont and past the face 

 of the Helderberg scarp, at 840 feet as the lowest. The latest flow of the ice- 

 impounded Mohawk waters was south of Amsterdam and past the face of the 

 scarp at Rotterdam. 



The copious drainage of the western slopes of the Adirondack* poured into a 

 lake held in the valley of Black river, with the production or a remarkable 

 expanse of sand plains. In the various features and relations which charac- 

 terize a glacial lake the Black lake is probably the finest example of a glacial 

 lake in the state (though not nearly so remarkable in complexity of drainage 

 and history as the Genesee waters). The earliest outflow of the differentiated 

 waters of the Black valley was southward past Remsen into the Mohawk lake, 

 with delta built at Trenton and Trenton Falls. The second escape was south- 

 westward, at Boonville, into the inferior Mohawk lake, with delta north of 

 Rome. The third stage had westward outflow, curving around the high ground 

 between the Black valley and the Ontario basin, at Copenhagen and Champion, 

 the flood pouring into lake Iroquois at Adams. 



CORRELATION OF THE HUDSONIAN AND THE ONTARIAN GLACIER LOBES 

 BY H. L. FAIRCHILD 



[Abstract] 



In the waning of the Labradorian ice body the Adirondack massif became 

 uncovered, at first as an island, with probable westward flow of the ice through 

 the Mohawk depression. Later the glacial flow was divided into a Champlain- 

 Hudson lobe and a Saint Lawrence-Ontario lobe. For a long time the Hud- 

 sonian lobe pushed an ice tongue westward into the lower Mohawk valley, 

 while the Ontarian lobe sent one eastward into the upper Mohawk valley. Im- 

 prisoned between the two opposing ice fronts the glacial waters stood at high 

 levels in the Mohawk and Schoharie valleys. As the waning ice margins re- 

 leased successively lower passes to southern drainage the waters fell accord- 

 ingly. 



The delta sand plains on the flanks of the Adirondacks and in the upper 

 Mohawk valley, with their various declining altitudes, show the successive 

 levels of the waters; and these levels were determined by the positions of the 

 ice margins with reference to a few critical cols or passes on the divide. 



The two papers were discussed together by A. P. Brigham, H. L. Fair- 

 child, and A. W. Grabau. 





