66 NEW YORK STATE MUSEUM 



in the narrow valleys the melting of an equal amount of ice would 

 produce a much more rapid recession, giving but little opportunity 

 for the deposition of material. Again at the northeastern ends of 

 the passes the ice tongues paused long enough to deposit another 

 series of moraines. Such recessional moraines blocking both ends 

 of the Cascade lakes fault-line valley have resulted in the basin 

 within which the lakes are now situated. Originally but one lake 

 occupied the depression. A similar group of moraines act as a 

 natural dam retaining the waters of the Lower Ausable lake. Man 

 has come to the aid of nature and reinforced and heightened it. It 

 is very likely that only one lake lay in the Ausable lake fault-line 

 valley before the accumulation of the delta sands of Shanty and 

 Haystack brooks. 



Doctor Kemp has already called attention to the morainal dam con- 

 fining Chapel pond. This long narrow ridge is an esker ; the glacial 

 deposit of a stream flowing beneath the ice. Another esker is excel- 

 lently well displayed beside the state highway from Keene to Eliza- 

 bethtown half way up " Spruce hill." It can be traced for nearly 

 one-fourth of a mile. 



The preglacial drainage has been modified by glacial material of 

 one kind or another in several localities. An excellent example of 

 stream diversion is south of the town of Keene on the northern 

 boundary of the quadrangle, in the East branch of the Ausable 

 river. In this comparatively broad valley we note an unnamed hill, 

 around the two sides of which the two highways leading to Keene 

 valley circle. To the west of the hill the present river rushes between 

 steep walls of syenite complexly involved with various Grenville 

 rocks, experiencing rapids and falls. It is clearly a postglacial chan- 

 nel and is one of the beauty spots in the quadrangle. On the other 

 side of the hill the preglacial channel is plainly visible although now 

 blocked by sands of a lateral delta. The accompanying map shows 

 the probable course taken by the branch before the invasion of the ice. 



Farther upstream a similar state of affairs is suspected, but not so 

 easily proved. Back of the Ausable Club (Beede on the map) the 

 present river leaves the fault-line valley, following a recently formed 

 gorge in anorthosite. One-half of a mile to the east the topography 

 and the sand plains seem to indicate that the preglacial channel fol- 

 lowed a direction across the bedrock, now under the eroded surface 

 of the terraces of the Saranac glacial waters, the probable course 

 being indicated by the road in its circuit around the golf links. 



