528 JOHN L. RICH 



CHANNEL TYPES 



The glacial channels of the Finger Lake region are of several 

 different types, representing various conditions of formation, ran- 

 ging from small streams at the ice margin to the outlet streams of large 

 glacial lakes. It has been found desirable in describing these channels 

 to classify them into five groups, based on the most common conditions 

 of formation. The following five types have been selected : 



I. Marginal. — Channels formed by streams flowing close along 

 the ice margin. 



II. Submarginal. — Channels of a broadly marginal nature; not, 

 however, following closely the edge of the ice; cutting across hill 

 spurs or behind small outlying hills. 



III. Lateral. — Channels formed by streams leaving the glacier 

 through a notch in the bordering hills and flowing laterally away 

 from the ice. 



IV. Morainic channels. — Channels formed while a moraine is 

 building by contemporaneous streams issuing from the ice. Often 

 indistinct; best developed in flat moraine near the end of an ice-lobe. 



V. Glacial lake outlets. — Channels formed by the outlet streams 

 of glacier-dammed lakes. 



It must be borne in mind that it is often difficult, if not impossible, 

 to draw sharp fines of distinction in all cases. This is necessarily so 

 because of the variations in conditions under which the channels were 

 formed. 



In this paper only selected examples of each type are described. 

 In so far as possible channels have been selected which illustrate well 

 the type, and at the same time show features of more than local interest. 



TYPE I. MARGINAL 



Slaterville channels. — One of the most typical channels of the 

 marginal type is found about two miles east-northeast of Slaterville 

 Springs (Dryden sheet, U.S.G.S.) on the east side of Six Mile Creek 

 valley at an elevation of about 1,640 feet near the top of the southmost 

 hill. The channel starts as a sfight trimming of the hill slope. This 

 increases gradually until at first a flat bench, and later a two-sided 

 channel is cut in the slope (Fig. i) . The channel bottom has a width 

 of about one hundred feet and is very flat and swampy. A profusion 



