ANCIENT WATER LEVELS OF CHAMPLAIN-IIUDSON VALLEYS 141 



a group of deep ice block holes and kame kettles, the most 

 extensive in the entire length of the Hudson and Champlain 

 valleys. This terrace begins on the south near the Hudson 

 river in a narrow shelving deposit having an elevation accord- 

 ing to the contoured map of about 420 feet. Two miles north 

 of the Hudson river, the terrace or at least a higher level of 

 the deposit attains an elevation of 482 feet. From this point 

 the front of the terrace trends northeastward toward Hound pond. 

 Following along the base of Luzerne mountain, the level of the 

 terrace rises to about 500 feet at the distance of 4 miles from the 

 Hudson river; and at French mountain station the surface attains 

 a bight of 548 feet. 



The front of the terrace passing northeastward at a distance 

 of 2 miles northwest of Glens Falls rises from 50 to 100 feet 

 above the more thinly drift-covered surface at its base. The 

 summit line of the terrace front rises to about 480 feet except 

 where gnawed back by streams. This frontal slope is an ill char- 

 acterized bluff neither lobate like the front of a delta built 

 in open water nor with stratified gravels and sands standing 

 at the angle of repose as in old stream-cut terraces now healed 

 by gravitative slipping. The detritus at the front is perceptibly 

 coarser than over the top remote from the brow of the slope 

 and boulders are not uncommon along its extent, an assem- 

 blage of features, weaker than usual, but indicating undoubt- 

 edly the deposition of the materials of the terrace in an open 

 space lying between the base of Luzerne mountain and the ice 

 mass which still lay over the central part of the Fort Edward 

 district. The large kettle and ice block holes representing out- 

 lying partially or wholly buried blocks of ice give strong sup- 

 port to this view. 



Patten's Mills terrace. Between Patten's Mills and Sugar Loaf 

 mountain in the southwest corner of Fort Ann township [see 

 Glens Falls quadrangle, pi, 14], the border of the large mass 

 of ice covering the Fort Edward district is again marked by 

 marginal deposits but in this case on the north. These deposits 

 assume the form of a high gravelly terrace attaining an eleva- 

 tion of about 520 feet near the southern margin, and sloping 

 gently northward, partially inclosing in that direction a lake- 



