NEW YORK STATE MUSEUM 



side of the island and in many places the waves have not yet 

 succeeded in removing the till. For instance, in Spoon bay, one 

 may remove the till and find scratched and polished bed rock 

 where the same is covered by water for half the year. Nearly 

 vertical cliffs rise from these beaches and yet the beach shelf is 

 glaciated. Plate 6 shows the character of the western portion 

 of the south cliff. Its upper edges have been rounded by glacial 

 action and but few large fragments of the wall have fallen since 

 glacial time. The eastern part of this cliff, which is nearly as 

 high, has been cut in rocks which dip easterly with sufficient angle 

 to expose strata that reached from the very bottom of the Chazv 

 bec 1 s to near their top. This cliff shows abundant signs of glacia- 

 tion and contains one large pothole about half way down its face. 

 At the base of this cliff is the wave-cut shelf shown partly exposed 

 in plate 7. Within a few feet of where the man is holding an 

 oar, the waves of the low water level have carried away some 

 fallen debris and exposed a bed of glacial till in which the dark, 

 washed, Trenton pebbles (still partially embedded) contrast 

 strongly with the pale, water-eroded surface of the clay. Nearer 

 the bank the clay of the till, at least in its upper portion, is some- 

 what interstratified with very fine sands due no doubt to glacial 

 drainage over the cliff. Such a drainage is indicated by the pot- 

 hole. A top dressing a foot and more thick, consisting of fallen 

 fragments from the cliff and heavy, rounded, granitic boulders, 

 about half and half, serves to break the force of the waves and 

 undertow. The heavier masses are well bedded in a coarse gravel 

 which becomes much finer nearer the bottom. The transition from 

 the clean, fine, washed gravel to the clay of the till is sharp and 

 distinct. This till was uncovered and then excavated to the depth 

 of 2 feet in two different places and found to contain only well 

 worn, polished, and scratched pebbles. 



The wave-cut bench is here more than 30 meters wide. The 

 cliff at the right is of hardest, massive, middle Chazy and on both 

 sides of this point streams of glacial till have cut down the weaker 

 rocks of the cliff and going seaward lowered the shelf level by 

 from 2 to 4 feet on both sides of the exposed portion shown in 

 plate 7. I Mate 8 shows a similar shelf at the same level ex- 

 tending far to the south and west of Garden island. The man 

 in the boat has his oar resting on the rock bottom more than a 

 hundred meters aut. Evidences of preglacial wave-cut shelves 



