CONTEMPORARY LOCAL GLACIAL LAKES. 449 



Spring water lake. — The valley of Hemlock lake was the basin of an 

 independent glacial lake, overflowing at Wayland into Susquehanna 

 drainage. The altitude of its outlet is a little over 1,400 feet, but the 

 main channel across the divide from the Dansville valley into which the 

 Hemlock waters were poured is 1,362 feet. This lake deserves fuller de- 

 scription than can here be given. The same is true of the two other 

 "finger" lakes, Canadice and Honeoye, contained in the Genesee hydro- 

 graphic area. 



TRIBUTARY TO GENESEE AREA. 



At least two instances are known where local glacial lakes outside the 

 Genesee basin poured their waters over the divide into the Genesee lakes. 

 These are both upon the east side of the area. 



The Rexville lake occupied the valley of Bennets creek and poured 

 over a divide about two miles above Rexville into the head of Cryder 

 creek. This pass is now traversed by the New York and Pennsylvania 

 railroad and has an altitude of 1,912 feet. It is about 700 to 800 feet 

 wide, partially buried under a detrital cone from the south slope, and 

 leads to a well marled channel in a winding rock gorge. 



The other instance is a lake in the valley of Canacadea creek, which 

 flows north into the Canisteo. We will name the lake after the creek. 

 The outlet was over a col into the north branch of Dykes creek. The 

 valleys and col are traversed by the main line of the Erie railroad. The 

 divide is a swamp col, 700 to 800 feet wide, with altitude of 1,777 feet. 

 The ancient channel is well defined, 400 to 600 feet wide, and partially 

 in rock- walls. 



3 



Subsequent morainal Lakes. 

 in genesee river. 



Doubtless many pondings of the Genesee river by morainal dams ex- 

 isted after the withdrawal of the glacial lakes. Where the river was able 

 to cut its way through the drift dam without interference of rock, the 

 positive evidence of such lake may be difficult to find. In two cases, 

 however, the river has made deep rock ravines and the evidence of mo- 

 rainal lakes is conclusive. These dams were at Portageville and Mount 

 Morris, and the lakes have already been referred to in the attempt to 

 show the reader the complexity of the static water phenomena. 



At Portageville the broad, deep valley was completely dammed with 

 drift, and the river found its outlet over the east rock-wall of the buried 

 valley. After cutting through perhaps 75 feet of drift the river had to 

 cut through about 125 feet of Portage shales before the lake was drained. 



