ANCIENT WATER LEVELS OF CHAMPLAIN-HUDSON VALLEYS 169 



plain valley. I have taken the level from the local contour of the 

 Willsboro quadrangle. 



Shore lines and deltas ahout Port Kent. By reference to the 

 topographic map, plate 21, giving a part of the Plattsburg quad- 

 rangle, it will be seen that shore lines and deltas are to be found 

 from Port Kent back to Keeseville on the Ausable river. 



Trembleau mountain on the south is thinly covered with drift 

 particularly on the lakeward slope from 500 feet downward. Much 

 of the steeper slope immediately west of Trembleau point has been 

 stripped of drift by wave action. Heavy till deposits farther 

 inland occasion the northern slope in the form of the broad spur 

 extending from the 600 foot contour line down to the 400 foot line. 

 Till again appears near the lake shore in Port Kent village; 

 though on top of the hill on the border of the streets as laid out 

 on the map a well was sunk some 12 feet in coarse waterworn 

 materials containing cobblestones up to 10 inches in diameter, 

 probably waveworn materials. 



Shore lines begin to appear first, as one descends Trembleau 

 mountain, at about 590 feet. The deposits of this stage suggest 

 the presence of ice, either floating or pan ice, by reason of the 

 angular blocks in the rude but essentially horizontal, often spitted, 

 beachlike deposits which can be traced where shown by the line 

 on the map. Definite wave-heaped beach ridges appear a few feet 

 lower at probably 580 to 585 feet in the elliptic hill crest shown on 

 the map. The stones are subrounded in this deposit inclosing a 

 shallow saucer-shaped depression in the center — the old lagoon of 

 this ofi'shore wave-heaped shoal. From this level traces of wave 

 marks in parallel roads or occasional lines of waterworn pebbles 

 (as along the road from Port Kent to the lowest notch in the 

 crest of the mountain) appear down to at least the levels of the 

 two churches in Port Kent. 



Near the old tollgate site, 1% miles west of Port Kent, the spur 

 of till before mentioned is cut back in the form of a good sea cliff 

 having a length of about % mile. The base of this cliff is at 

 about 340 feet and is confronted by one of the delta levels of the 

 Ausable. It would appear that the heaviest and longest wave 

 action took place locally at this level. That the escarpment in the 

 till is due to wave cutting rather than to stream cutting during the 



