88 NEW YORK STATE MUSEUM 



ured, it is 33 feet long, 27 feet wide and 25 feet high. Since its 

 deposition by the ice it has been split open along a joint surface. 

 Plate ii shows the appearance of this boulder. It was transported 

 at least several miles, since the nearest outcrops of Marcy anor- 

 thosite are that far to the north. 



Two remarkable boulders of Marcy anorthosite are shown in 

 plate 12. They are close to the road two-thirds of a mile south of 

 Wolf pond. Both are notably rounded, suggesting transportation 

 for a number of miles at least. One of them, at least 14 feet in 

 diameter, rests in a remarkably balanced position upon the other 

 large one which is partially buried in the glacial drift. It scarcely 

 seems possible that the upper boulder can retain such a position, 

 and yet it remains there in spite of an attempt some years ago to 

 pry it off. 



Kames and eskers. Kames and eskers definitely recognizable 

 as such are not common in the quadrangle. In the areas of heavy 

 glacial and fluvio-glacial deposits, some of the little hills strongly 

 suggest their origin as kames, but, since their structure is rarely 

 ever revealed, this is not certain. 



But one clearly defined esker was observed, and this is a very 

 fine one. It lies just northwest of Schroon Lake village with a 

 sinuous course and a general north-south strike for more than two- 

 thirds of a mile. Its northern end comes against the base of the 

 steep hill. The contour map only roughly suggests its position. 

 It consists of sand and well-rounded small to large pebbles. In 

 height it varies from 20 to 75 feet. Toward the north where it is 

 highest and covered with trees, it is a very steep-sided narrow 

 ridge. Plate 13 shows part of it toward the south in an open field 

 where it is neither so high nor so sharply defined. This esker was 

 probably formed by a debris-laden stream from the hillside upon 

 or under the ice of the great waning ice sheet which still lay in the 

 valley. 



Lakes and Their Deposits 



Extinct lakes. Glacial Lake Pottersville. This former large lake 

 was first recognized by the writer and described in his report on 

 the North Creek quadrangle. 1 It is named from the village of 

 Pottersville which lies on the old lake bottom. Its waters spread 

 through the Schroon valley from near Chestertown, over the site 

 of Schroon lake, and to north of North Hudson. Branches of the 



1 N. Y. State Mus. Bui. 170, p. 70-72. 1914. 



