32 . NEW YORK STATE MUSEUM 



the last withdrawal of the ice sheet to the north, the present Hudson 

 river (under conditions presently to be stated) entered the valley, 

 cutting a channel into the till and eventually producing the existing 

 features as above described. 



The writer believes that the last of these three interpretations is 

 the true one. A somewhat fuller statement may now be given. 



EVIDENCES OF AN INTERGLACIAL EPOCH 



In preglacial times the Luzerne river occupied the Paleozoic rock 

 valley north and south of Corinth. 



A preglacial stream having its source near the western base of 

 Mount McGregor discharged into the Luzerne river at Corinth. A 

 portion of the valley of this stream is still open to inspection. Just 

 east of Corinth an old stream channel communicates with the pres- 

 ent river channel at the upper end of the gorge on the south side. 

 Except for a short distance back from the river it is rilled in with 

 till but it can be traced as a depression, bordered on the east side 

 by a gradually diminishing slope, about one-eighth of a mile back 

 from the river. This depression is indicated by the contour lines of 

 the sheet. Where it joins the river channel the old channel has the 

 character of a gorge with bed and walls of sandstone rock. The 

 east wall is here a nearly vertical cliff and is continuous with the 

 south wall of the river gorge. It is evident that the gorge end of 

 the channel has been scoured 'out and its walls undercut by the 

 currents of the river. Its bed now stands at about 10 feet above 

 the level of the river, or at 530 feet elevation. The width of the 

 channel at the gorge end is about 50 feet. 



We may note in passing that the existence of this old stream 

 channel affords a datum for the elevation of the bed of the pre- 

 glacial Luzerne river in the locality of Corinth. Assuming it to 

 have been approximately the same as that of its tributary where 

 the channel of the latter is exposed, we have 530 feet. Rock ex- 

 posures in the beds of existent streams are in accord with this 

 determination. At Luzerne, 6 miles above Corinth, at the foot of 

 the rapids over bedrock, the level of the river is 540 feet. South 

 of Corinth the present drainage streams of the central basin have 

 their beds on glacial sands and clays or on glacial till, as far south 

 as Middle Grove, where in the bed of the Kayaderosseras, rock 

 is exposed at the level of 520 feet. These data indicate a moderate 

 and somewhat uniform fall in the bed of the preglacial river, 

 as would be the case in an old stream. 



