ANCIENT WATER LEVELS OF CH A MPLAIN— HUDSON VALLEYS 1G3 



As regards the position of the ice front on the northern flank 

 of the hill, it should be stated that as noted by Mr Gilbert the 

 highest well defined and clearly demonstrable beach along this 

 line is at 450 feet above sea level. But above this beach occurs a 

 succession of rude terraces with coarse and often rather angular 

 blocks from just above the 450 foot line to about 570 feet. Some 

 of these are lines strikingly level for long distances; yet other 

 parts of this system are inclined. All of them and particularly 

 the highest show considerable cutting into the till cover of the 

 hill. A till cliff is conspicuous at a number of localities on the 

 north side of Covey hill near the 570 foot level according to my 

 aneroid readings. Waterworn pebbles and characteristic beach 

 wall structure are apparently absent. Mr Gilbert according to 

 his notes in his search for beaches ruled all these higher 

 lines out, if I understand his notes correctly, because of their lack 

 of horizontality. Prof. A. P. Coleman who examined them in 

 my company in 1903 hesitated at the time to pronounce them 

 beaches. They lie for the most part in the zone of certain high 

 and coarse beaches of angular and shingly debris which can be 

 traced to the southeastward on the northern part of the Mooers 

 quadrangle. The deposits deserve further study with careful 

 leveling and mapping. If not due to powerful waves these 

 terraces seem to me to demand powerful currents acting in the 

 manner of the streams which Mr Gilbert and later Professor Fair- 

 child have traced along the ice front in central New York between 

 Syracuse and Eome. Such stream action between the ice front 

 and the slope of the hill would cut effectively and make a part of 

 the stream bed in the till with one bank of that material, and 

 the other half of the bed might be formed by the ice with the 

 bank on that side also of ice. It is to be expected that, as soon 

 as the ice withdrew somewhat from the northern face of the upper 

 part of Covey hill, the heavy discharge of waters which had 

 taken place through the Gulf would have been diverted to the 

 north side of the hill at . a lower level. Farther south on the 

 Champlain side there was a glacial lake with constantly lowering 

 stages into which these torrential spillway levels would merge. 

 Such is the interpretation which I have placed on these terraces 

 above the marine limit of 450 feet on the northern flank of Covey 

 hill. 



