CLOSING PHASE OF GLACIATION IN NEW YORK 737 



exposed land surrounded by the ice-sheet. In an unpublished paper describ- 

 ing the glacial waters of the Mohawk and Black valleys it is shown that the 

 high Adirondacks were at one time in the waning of the Labradorean ice- 

 sheet exposed as bare highlands while surrounded by ice. The Hudson ice 

 lobe and the Ontario lobe were yet united by a neck or strait of ice in the 

 Mohawk Valley, and the drainage from the Adirondack area was southward 

 across the strait of ice into the headwaters of the Susquehanna River. 



CLOSING PHASE OF GLACIATION IN NEW YORK 

 BY H. L. FAIRCHILD 



(Abstract) 



As the Labradorean ice-sheet melted away from the north border of New 

 York State, it allowed the water of the ice-bound Lake Iroquois to escape at 

 Covey Hill Gulf and to pass around the northeast slope of the Adirondack 

 highland. Being confined and directed l)y the ice-border, this stream-flow 

 produced the extensive areas of bare rock in the towns of Mooers, Altona, 

 and Beekmantown. formerly described by Woodworth.^ The later stream- 

 flow along the Altona rocks determined the level of a narrow lake lying north- 

 westward, into which Lake Iroquois was lowered by the waning of the ice- 

 front on Covey Hill, and for a time this lake succeeded Iroquois in the Onta- 

 rio basin. It is proposed to call this water Lake Emmons (after Ebenezer 

 Emmons, whose district in the first geologic survey of the State covered this 

 area). The further weakening of the ice-border finally allowed Lake Ver- 

 mont (named by Woodworth), which had previously been confined to the 

 Champlain ^'alley, to succeed Lake Emmons, and in turn to occupy the Onta- 

 rio basin. • It is proposed to call this expanded water Lake Vermont-New 

 York. These two water planes in the Ontario basin, inferior to Iroquois, are 

 represented chiefly by delta sand plains on the larger streams. Eventually 

 the waning of the ice east of the Champlain embayment allowed the glacial 

 waters to become confluent with the sea, and the sealevel waters were thus 

 established in both the Champlain and Ontario basins at the same time. The 

 height of the marine beaches about Covey Hill is 525 feet, which definitely 

 gives the amount of land uplift on the international boundaiy since the ocean 

 transgressed that area. Maps exhibit the glacial drainage channels, the 

 deltas, and the shorelines of the three water planes in the Champlain dis- 

 trict and* the four planes in the Ontario district. 



Discussion 



Dr. J. W. Spencer : The first survey of the Iroquois beach in northern New 

 York was made by myself. The continuous shoreline could be traced to only 

 a few miles east of Watertown, where I measured it 730 feet (subse(iuently 

 by Fairchild at 783). Beyond, I found a series of magnificent deltas and 

 sand plains. These were measured and regarded by me as the continuation 

 of the Iroquois beach. Dr. Gilbert and I went over the field together. He 

 regarded them as belonging to separate glacial lakes. Now Professor Fair- 

 child extends my original surveys farther east, although shore features are 



s New York State Museum bulletins, 83, 84. 



