228 NEW YORK STATE MUSEUM 



below 500 feet, but a nuiuber occur east of Troy between 500 and 

 720 feet, and one group on the Colioes sheet at GOO feet. On the 

 nortliern part of the Schuylerville sheet, kettle holes come in again 

 at 300 feet near Moreau pond; and examples may be encountered 

 along the rising profile line to the north on the Glens Falls sheet 

 in the Glen lake district with inclosing contours at 420 feet, and 

 still farther north on the Ticonderoga sheet at Street Koad with 

 inclosing contours at 540 feet. This line of kettle deposits risc^ 

 northward at the rate of 3.2 feet a mile, or more steeply than the 

 earlier ones on the south. 



Comparing these three segments of lowest lines of kettle holes 

 in the Hudson-Champlain trough, we observe that each going 

 northward represents a successive later stage of the ice retreat, 

 that each profile line on the north is successively more steeply 

 tilted southward, and that these lines lie slightly oblique to a 

 general line of tilted levels which may be drawn from the interna- 

 tional boundary on the north to New York Narrows on the south. 



It is reasonable to suppose that this increase in the tilt rate 

 toward the north is not an original feature but dejiends on a 

 change which has taken place in the attitude of the land, a change 

 which is demonstrated as being a tilt in the same direction by an 

 abundance of facts drawn from other kinds of evidence. It is 

 furthermore probable therefore that each of these segments of 

 kettles in tilted profile lines was more nearly horizonital originally 

 than now and that the steepest of them was as flat as is now the 

 least inclined. If this be true it follows that the degree of tilting 

 increases northward from New York Narrows to Lake Cham])lnin. 



EVIDENCE FROM POTHOLES NEAR THE HUDSON GORGE 



Glacial potholes, the so called giant kettles, are of value in 

 determining the relation of land and sea Avhen they occur in 

 abandoned water ways or localities where glacial streams can 

 be shown to have been the cause of their making. A number of 

 localities of potholes have been described. A ])nir of these Avater- 

 worn holes may be seen in the rocks at Wa])pinger Falls at an 

 elevation of about 45 feet above sea level. Professor Osborn has 

 described a glacial pothole near Catskill N. Y. N. L. Britlon 

 noticed large ones near AVilliamsbridgo. O. P. Hubbard has de- 

 scribed i)otholes opposite Catskill near the Hudson. Those on the 



