398 



SCIENCE 



[N. S. Vol. XXVI. No. 665 



and Covey hill north of it constitute a 

 locality of critical importance in the study 

 of water-levels in the Champlain and St. 

 Lawrence valleys. "The Gulf" pertains 

 to the closing stages of the great ice- 

 dammed lakes which formed in front of 

 the ice in its retreat from the territory of 

 the United States. When ' ' The Gulf ' ' was 

 being excavated by a powerful torrent of 

 water, the ice-sheet still hugged the north- 

 ern side of Covey hill, itself the northern- 

 most spur of the Adirondacks. 



The waters which entered "The Gulf" 

 came from the west, the region of Lake 

 Iroquois, whose waters would have taken 

 this path after the ice retreat offered a 

 lower outlet than that at Rome. The 

 waters passed from "The Gulf" into Lake 

 Vermont, the preglacial lake occupying the 

 valley of the present Lake Champlain. 

 Lake Vermont could not at this stage of 

 its existence have risen above the surface 

 of the water in the waterfall pools of ' ' The 

 Gulf." The lower lake is now 645 feet 

 above sea-level. The sea could not at this 

 latitude have stood higher than the bottom 

 of "The Gulf." 



With the further retreat of the ice from 

 the northern slope of Covey hill the water, 

 which had previously discharged through 

 "The Gulf" on the south side of the hill, 

 flowed around the northern slope of the 

 hill and emptied into the sea. The salt 

 water came in, and the history of the great 

 glacial lake was completed. 



Signs of wave action occur on the Cham- ■ 

 plain sifle of the Adirondacks as high as 

 720 feet, but these higher water levels do 

 not continue about the northern side of 

 Covey hill north of "The Gulf." A good 

 beach is continuous from the Champlain 

 valley about Covey hill into the upper St. 

 Lawrence valley with an altitude of 450 

 feet at Covey hill. Higher signs of prob- 

 able wave action occur up to 570 feet, merg- 

 ing into beaches evidently made by tor- 



rential waters confined between the hill- 

 side and the retreating ice-front. 



' ' The Gulf ' ' was properly understood by 

 Ebenezer Emmons to have been made by a 

 powerful torrent flowing where now no 

 stream can flow. Gilbert, with the knowl- 

 edge of the glacial theory, sought for a 

 torrent spillway along the retreating ice- 

 sheet, and considered/ 'The Gulf" the out- 

 let for the glacial waters. "The Gulf" 

 therefore is an integral part of the wonder- 

 ful story of the great glacial lakes, and 

 the political chance which has drawn the 

 boundary line between Canada and the 

 United States across "The Gulf" serves 

 doubly to remind us of its living type, the 

 gorge of Niagara. 



On Thursday, July 4, those who had 

 taken the preliminary trip to Covey hill 

 drove from Mooers southward to West 

 Cliazy along many abandoned shorelines, 

 at elevations varying from 300 to 600 feet 

 above the present sea-level. At West Chazy 

 others joined the party from Plattsburg, 

 and all met on Cobblestone hill, where a 

 halt was made for an hour to study the 

 remarkable beaches of cobbles showing 

 pronounced bars, spits and hooks, at levels 

 of 600 feet and over above sealevel. 



These beaches of heavy glacial detritus 

 were laid down in a fresh-water glacial 

 lake, when the ice stood a short distance 

 north of this point, by the waters discharg- 

 ing from the northwest over Flat Rock 

 from the Altona spillway. 



Thence the party drove across the bare 

 Potsdam sandstone over the Altona spill- 

 way, where striking evidences were seen 

 of the scouring action of torrential glacial 

 watei's. After lunch at a spring of water 

 running from the Potsdam sandstone in the 

 spillway the party listened to a talk by 

 TI. L. Fairchild on 



IROQUOIS EXTINCTION 



Lake Iroquois was the great glacial water 



