OUTLET AND WATER-LEVELS OF WELLSVILLE LAKE. 435 



to the Oswayo creek at Shinglehouse the waters are sluggish. The swamp 

 and the slopes of the gorge are occupied with primeval forest, and the 

 dimensions could only be estimated roughly. The width of the rock- 

 gorge at bottom was judged to be about 1,000 feet. The weathering of 

 the steep walls of soft shales has produced talus slopes and detrital cones 

 which bury the edges of the old channel and over which the wagon-road 

 climbs in order to avoid the swamp. The middle of the channel is buried 

 under vegetal accumulation, the swamp being, it was estimated, 40 to 60 

 rods wide. The rock-walls, which are steeper than any preglacial valley 

 slopes, are perhaps over 1,000 feet high. Apparently this was a pregla- 

 cial col which has been deepened and widened by the glacial waters. 

 The amount of down-cutting by the glacial stream is suggested by the 

 height of a delta at the mouth of the Stone Dam gully near the east end 

 of the gorge, which was estimated to be 70 or 80 feet higher than the 

 divide, indicating a lowering of the channel of not less than 60 or 70 feet. 

 Very likely it was greater. The present altitude of the col is given by 

 Mr Pierce as 1,600 feet. 



Water-levels. — In the upper part of the Genesee valley, from the forks 

 of the river to below Wellsville, are numerous conspicuous phenomena 

 of static water which correlate with the Stone Dam outlet. Many of these 

 terraces were observed, and some of them measured, before the outlet 

 was discovered. At that time they were puzzling, as it was not known 

 that there was any pass through the divide so near down to the grade of 

 the valley. 



It is probable that delta deposits and wave-cut terraces will be found 

 in the valle3^s of the headwaters at an altitude near 1,700 feet or higher, 

 but an examination has not been made. At Genesee village there are 

 several good plateaus of water-worn material. Taking the station of the 

 Buffalo and Susquehanna railroad as datum at 1,624, the cemetery ter- 

 race, south of the village, is 1,734 (aneroid). Nearly corresponding ter- 

 races are seen upon the west and northivest and shoreline benchings upon 

 the east. Northeast of the village, one-half mile up Cryder creek, are 

 gravel plateaus at 1,690 (aneroid). Levels of the same erosion plane are 

 seen at Shongo station, north of Genesee. Near Graves crossing is a flat- 

 topped, butte-like plateau, 1,670 (aneroid), with a similar level at the 

 mouth of a west-side creek. Fine terraces are seen in the northward dis- 

 tance at corresponding height. A terrace near the east end of the channel 

 was estimated at 1,680. At Stannards Corners, toward Wellsville, are 

 conspicuous plateaus and terraces, unmeasured, but certainly of a plane 

 similar to those mentioned above. Within two or three miles of Wells- 

 ville are pronounced levels, estimated at somewhere between 1,620 and 

 1,650. 



