PLEISTOCENE MARINE SUBMERGENCE 55 



The upper swamp was estimated as one-fourth of a mile long, with 

 aneroid altitude 765 feet. The lower filling was made 740 feet, 

 the marine level. The total length of the swamps and rock piles 

 was thought to be nearly a mile. This may be regarded as the 

 delta of the Covey river at the sea level, during its latest flow. 



The rock bottom of the river channel is loio feet altitude on the 

 divide. The limit of visible water work on both the north and 

 south banks is about 1030 feet. The granite boundary monument 

 on the south side of the ravine has an altitude of 929 feet at the 

 base and 934 feet for the top. The altitudes given on the Churu- 

 busco sheet for the boundary monuments are all for " top of monu- 

 ment." On the Chateaugay sheet the altitudes refer to the base of 

 monuments. 



North slope and shore lines of Covey hill. The steep north and 

 northeast slopes of Covey hill are mostly in forest, with only a few 

 small clearings. A traverse was made down the north slope, but 

 the line of strongest pressure and longest hold by the ice front 

 must have been on the northeast ' face. The surface of the north 

 slope is gradual and fairly smooth, such as would be expected of 

 a strongly glaciated surface, down to lOio feet, corrected aneroid. 

 Below that occur rock ledges, benches and irregular terraces, such 

 as belong to steep slopes cut by rivers held to their work by the 

 forceful glacier. 



From over 1000 feet down to over 700 feet the slope must have 

 been eroded by the profuse waters of the Iroquois downdraining. 

 Below about 720 feet, allowing 20 or 30 feet of cutting below 

 static water level, the slopes were subjected to wave work of the 

 sea-level water. Below the marine plane the steeper slopes show 

 the ledges and rock piles due to wave action, while the moderate 

 slopes carry embankments of wave construction. 



The evidence of wave work at 740 feet is clear at all points 

 where the plane has been examined. On the highway leading down 

 the east side of the hill a well-defined cliff occurs at the critical 

 level, and others at lower levels, especially at about 640 to 625 

 feet. On the north and south road, 2 miles west of the hilltop, 

 the level appears in terraces at the angles in the road. Three miles 

 farther west, by the four road angles, distinct cliffs show on the 

 south, and delta sands by the Outarde river at 725 to 730 feet. The 

 shore line can be traced along the road leading southwest; and on 

 the road leading northwest, 2 miles southwest from Franklin 

 Center, strong bars cross the road from about 725 down to about 

 660 feet. At Frontier the shore passes back into New York, where 



