GEOLOGY OF THE LAKE PLACID QUADRANGLE 'J'J 



three sets of deltas in the Keene valley. It has fallen to the writer 

 to attack the problems of the glacial lakes of the east central 

 Adirondacks, and to attempt to translate something of the wonder- 

 ful' history. In such pioneer work mistakes and faulty interpre- 

 tations are apt to appear, for it is impossible to avoid errors. 



In dealing with the glacial lakes the writer has, for convenience, 

 classified them into three sections : ( i ) the western section, that 

 is, the region around Lake Placid, to the west of the Wilmington 

 notch; (2) the eastern section, or the Keene valley division in the 

 valley of the East branch of the Ausable river; and (3) the Eliza- 

 betlitown valley group. The last section does not come under dis- 

 cussion here. 



Upper series : western section. As the ice sheet began to 

 wane, the highest peaks of the Adirondacks were the first to be 

 uncovered, playing the role of islands in a sea of ice.^ Slowly these 

 islands became larger, surrounded by a growing accumulation of 

 water impounded by the ice. These waters found escape over the 

 ice to the south and eventually passed to Susquehanna drainage. 

 This process of melting was continued until entire mountain ranges 

 were exposed. 



The South Meadozvs lake. The highest definite level recog- 

 nized by the writer in the Adirondacks, as shown by sand plains, 

 terraces and beaches, is one ranging from 1940 to 2210 feet in 

 altitude. When this level was first appreciated some hesitation 

 was felt in describing it as glacial, for no shore-line features or 

 outlets had been noted. It was considered as outwash plains formed 

 by aggrading glacial streams that flowed from the melting ice, but 

 as extended field work was undertaken these lake phenomena were 

 discovered, or strongly suspected, and hence the true nature of the 

 plains was established. 



The best development of the glacial deposits of this lake is in the 

 northwest corner of the Mt Marcy sheet in the South Meadows 

 country ; hence the name — South Meadows lake. As can be seen 

 in figure 2, the writer conceives that it covered the southwest por- 

 tion of the Lake Placid quadrangle and the corners of the adjacent 

 sheets. The ice consisted of three lobes : one covered the greater 

 portion of the Saranac sheet ; the second lobe was fed through 

 the narrow passes to the east and west of the Whiteface-Esther- 

 Wilmington massif and covered the territory where Lake Placid 



1 Fairchild, H. L., N. Y. State Mus. Bui. 160, pi. 11. 



