MARGINAL GLACIAL DRAINAGE FEATURES IN THE 

 FINGER LAKE REGION^ 



JOHN L. RICH 



Cornell University, Ithaca, N. Y. 



A study of a considerable number of the channels or scourways 

 formed by streams associated with the Pleistocene ice sheet in the 

 southern Finger Lake region of New York has served to bring out 

 many features of more than local interest and importance, both as to 

 the broader phases of glaciation in this part of New York State, and 

 as to the value of a study of such channels as an aid in working out the 

 glacial geology of a region. 



This study has a distinct bearing on the interglacial problem in 

 that several of these channels give conclusive evidence of more than 

 one stage of glaciation, while one points strongly to three or more such 

 stages with corresponding interglacial epochs, some of which seem to 

 have been considerably longer than post-glacial time. Other channels 

 are so situated as to make possible a fairly accurate estimate of the 

 slope of the ice margin along the valley tongues. Still another 

 furnishes proof of an extensive sinking of the surface consequent upon 

 the melting-out of a large block of buried ice — a phenomenon, the 

 importance of which seems not to be fully appreciated. 



The Finger Lake region, lying as it does along the belt of the great 

 recessional moraines of the Wisconsin ice sheet, is especially favorable 

 for the study of marginal glacial drainage features. The long halts 

 of the glacier, while the moraines were building, gave ample time for 

 the associated streams to carve for themselves distinct channels 

 which, now that the ice is gone, are in most cases left dry and entirely 

 out of harmony with the present drainage. 



I This paper is an abstract of a thesis presented to the faculty of Cornell University 

 in June, 1907, as a requirement for a major in Physiography. The work vi^as under- 

 taken at the suggestion of Professor R. S. Tarr, to whom the writer is indebted for 

 helpful suggestions, and for the location of many of the channels herein described. In 

 the course of folio work for the U. S. Geological Survey, Professor Tarr discovered 

 several of these channels, some of which are described in his report soon to be pubUshed 

 by the Geological Survey. 



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