i8 



NEW YORK STATE MUSEUM 



Four miles north of Mayville and over a mile southeast of Pros- 

 pect station on the Pennsylvania Railroad is a short channel by the 

 four-corners at the "Elm Flat" church, with altitude of 1340 feet. 

 This is at the head of the swamp in the "big inlet" of Chautauqua 

 lake and could have carried the overflow of only a limited area and 

 for a short time. 



The next outlet is at the head of Bear lake valley, 3 miles south- 

 east of Brocton. This is a broad swamp col, still in timber, with 

 map altitude of 1320 feet, which carried a heavy drainage for 

 some time. The close correspondence in present altitude between 

 these several channels is probably merely coincident. The north- 

 ward tilting of the region in Postglacial time has lifted the 

 Bear Lake outlet 10 to 15 feet higher, as compared with the Big 

 Inlet pass, than it was when effective. 



The col 5 miles south of Fredonia, between the heads of Canada- 

 way and Cassadaga creeks, must have been the overflow point for a 

 large volume of water. It lies close to the Upper Cassadaga lake 

 in the valley moraine with altitude not much over 1300 feet, but 

 does not exhibit clear channel characters. This seeming incon- 

 sistency and the peculiar features and relationship were discussed 

 in the 20th Annual Report of the State Geologist, pages 132-35. 



Passing eastward we find three groups of cols at the heads of 

 three branches of the Conewango creek [see pi. 3]. The only well 

 defined channel is on the western col, i£ miles west of Mud lake in 

 the town of Arkwright. The waters of Walnut creek valley found 

 escape here over to the west branch of the Conewango at altitude 

 of 1420. While the drift filling of the broad south-leading valleys 

 shows that they carried heavy detritus-laden floods from the melting 

 ice front, it would seem that little water passed across the cols into 

 the valleys of the North branch and the Slab City branch of the 

 Conewango, apparently for the reason that the conformation of the 

 ice front to the topography was such that little was ponded here 

 north of the divide. From south of Forest ville eastward to Perry s- 

 burg no basins faced the ice front and the drainage was fairly free 

 past the ice to the westward. 



No other cols across the main divide between Erie and Allegany 

 waters have any relation to the glacial overflow in our district. The 

 passes at the heads of the several strong north-sloping valleys in 

 Erie and Wyoming counties simply carried their waters over to the 

 Cattaraugus basin, from whence it found further escape by chan- 

 nels above described. Three miles northwest of Cherry Creek is a 

 fine channel which was the outlet to Farrington Hollow glacial 

 lake, but both features are wholly in southern drainage. 



