CONTEMPORARY LOCAL GLACIAL LAKES. 447 



at least such relation to the river valley that the lobing of the ice-front 

 in the latter would dam the mouth of the side valley while the head of 

 the valley was open. 



The directions of lateral stream drainage, as shown by the map, would 

 seem to make such a damming a certainty for all the principal west side 

 streams from the head waters-down to Caneadea creek, and also for Oatka 

 creek. For the east side it was certainly true of the Canaseraga, and also 

 of the valleys of the western " finger " lakes, Conesus, Hemlock, Canadice 

 and Honeoye. A multitude of lakelets must have had a brief existence 

 in the great number of elevated and isolated valleys in which lie the 

 sources of drainage, but it is impossible to consider these. A few of 

 the more important lakes of this class will be briefly described as ex- 

 amples. 



Knight Creek lake. — The upper part of the valley of Knight creek held 

 a glacial lake, the overflow of which occupied the gorge east of Bolivar. 

 In looking for possible outlets of the Genesee lakes this pass was exam- 

 ined and was found to have been the channel of an extinct stream of 

 considerable size, but not sufficiently large to carry the drainage of the 

 Genesee glacier. The subsequent discovery of the low Stone Dam outlet 

 of the Genesee waters at once explained the Bolivar channel as being the 

 outlet of only the local Knight Creek lake. 



This channel is a winding mountain gorge, two or three miles in length, 

 holding now only a small stream. The high walls are rock, the bottom 

 flat and perhaps 600 feet wide, of gentle, steady grade to the col, which 

 is about five miles from Bolivar. The divide is swampy on the Genesee 

 side, and is reported to be drift. 



A thousand oil derricks rising through the timber recall the da3''S of 

 the Allegheny county oil boom, when a narrow-gauge railroad used this 

 pass to reach Wellsville. An old profile of this abandoned road makes 

 the altitude of the divide 1,997 (?) feet. No observations have been made 

 upon the phenomena in the local lake basin. 



Friendship {Van Campens Creek) lake. — North of Bolivar and Richburg 

 are two cols known locally as " East notch " and " West notch." Each 

 of these seems to have been an outlet of small and transient lakes in the 

 two forks of the south branch of Van Campens creek. The east notch 

 shows little evidence of stream action and is definitely higher than the 

 west notch. The latter has a sharp ridge at the divide, but a well defined, 

 although small, scour way leading south to Richburg. A narrow-gauge 

 branch of the Lackawanna and Southwestern railroad formerly traversed 

 this pass, but the altitude is not known. The small lake drained by this 

 outlet we will call the Wirt Center lake. 



LIU— BuLT,. Geol. Soc. Am., Vol. 7, 1895. 



