130 



NEW YORK STATE MUSEUM 



village of Saranac Lake are conspicuous, but more striking is an 

 elongated (eskeroid) ridge north of Jones pond, the surface of which 

 is dimpled with small, block kettle holes. To the west of Paul 

 Smith's there are two narrow winding ridges that are eskers, which 

 represent the deposits of sand and gravel formed by streams flowing 

 southward under the thin edge of the ice sheet during its northward 

 retreat. The whole region is deeply buried in glacial drift of various 

 sorts, ranging from the finest of sand to huge boulders, some of which 

 are rocks quite foreign to the region. Boulders of Potsdam sand- 

 stone, of granites and of gneisses from Canada are frequently 

 encountered. The mantle of glacial material is spread over the tops 

 of the hills rendering the exposures of the rocks beneath infrequent, 



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Fig. i Ideal cross section of a delta. BR=bedrock, D=delta, L=lake, S=surface 



of water. 



thus adding great difficulties to the work of mapping the igneous 

 rocks. Geological crudities in the accompanying map give evidence 

 of the thickness of the till. 



Glacial moraines have in place dammed up existing valleys and 

 river courses, forming many of the lakes of the region and forcing 

 the streams to take new directions. Lake Placid is a striking example 

 of a lake formed in this way. The town of Lake Placid is situated 

 upon the moraine that has dammed and inundated two parallel 

 fault line valleys. Faulting, following cross fault lines, has produced 

 the islands, thus forming a ladder-shaped body of water. Lake 

 Clear is a similar one on a smaller scale. Details of its origin will 



