56 NEW YORK STATE MUSEUM 



filled up. This water could not escape northward, for there all the 

 country was still solidly mantled by the glacier hundreds of feet 

 thick ; it could not escape laterally for the valley sides rose to eleva- 

 tions of 1500 and more feet. Accordingly its level was determined 

 by the lowest hollow in the morainic barrier that had been built up 

 across the valley and there the water of this local, proglacial lake 

 overflowed to the south. To this body of water Fairchild has applied 

 the name of Lake Cardiff.'' The main overflow later may have been 

 through a gap at an elevation of about 1180 feet that occurs just to 

 the west of the road intersection north of Mud lake. But while the 

 ice was apparently still blocking this lowest gap in the moraine an 

 incipient lake seems already to have formed on the east side and its 

 waters found escape through a gap at 1260 feet height, for the stream 

 of this overflow made a very distinct and typical channelway, now 

 altogether dry, parallel to the improved state highway leading north, 

 just outside the village of Tully Center. On the topographic map 

 this lake outflow channel is indicated by a tonguelike curve north- 

 ward of the 1260 foot contour line. It is immediately parallel to the 

 state road and is illustrated by plate 13, looking south. 



The channel is seen on the left side of the picture and its cross- 

 section form is most clearly discernible in the part between the 

 barns on the right and the road on the left. Its right bank is in the 

 loose morainic stuff and is most typical ; the other bank is against the 

 rock of the valley side. 



The wide flat bottom and the low, though steplike, bank on the 

 right are characteristic of such channelway s. While functioning 

 they flowed a stream of large volume continually replenished by the 

 ice melting, which swept along its course in much the same way 

 that the upper Niagara river on a larger scale now discharges the 

 drainage of the Great Lakes. In the present instance the current 

 was not so clear as is the Niagara water for it was derived from the 

 ice-front immediately at hand, and this furnished a large quantity of 

 sediment that was carried out of the small lake before it could settle 

 to the bottom. Perhaps it would be better to class this scourway 

 with what are termed marginal or morainic channels, for the ice 

 influence and the sediment load the ice furnished no doubt gave it 

 the predominating characteristics of this class, but, in its later 

 phases at least, it must have had a lake fore-bay, hence may properly 

 also be called a lake outflow channel. 



* Fairchild, H. L., Glacial Waters in the Finger Lakes Region, Bui. Geol. 

 Soc. of Amen, 1899, 10 : 57-58. 



