434 H. L. FAIRCHILD — GLACIAL GENESEE LAKES. 



The waters of the east-branch lake, by the Ulysses-Brooklancl col, 

 flowed to the Susquehanna river; those of the other two lakes reached 

 the Allegan}^ river. 



With the further recession of the ice-front it is possible that for a brief 

 period the eastern lake found a lower outlet and that the two eastern 

 lakes blended into one. It is doubtful if the outlet by Bingham, toward 

 Harrison valley, the lowest of the east-side cols, was opened before the 

 junction of the valle}'' was uncovered, thus allowing all the waters to 

 flow west by the Oswayo outlet. In any case, this phase was so brief 

 that, with the present uncertainty, no further note of it is taken. 



SECOND STAGE: PENNSYLVANIA LAKE. 



Outlet. — The outlet was by Rose lake col to Oswa^'o creek and Alle- 

 gany river. 



As soon as the ice had uncovered the high land between the creeks 

 south of Genesee village, the three primary lakes blended into a single 

 sheet of water having the level of the lowest outlet. This was undoubt- 

 edly the outlet of the Avest-branch lake, by Rose lake to the Oswayo creek, 

 which is about 200 feet lower than the more southern outlets and at least 

 100 feet lower than the Bingham outlet. From the scanty information 

 attainable, this is believed to be the most capacious of the headwater 

 outlets. 



Life history. — This lake could not have existed long, as the northward 

 shifting of the ice-front only a few miles opened a much lower pass and 

 inaugurated a more important stage of the glacial waters. 



THIRD STAGE: WELLSVILLE LAKE. 



OiUlet. — The outlet was by " Stone Dam " col to Honeoye creek, Oswayo 

 creek and Allegany river. 



From tlie parallel of the Genesee forks north to the parallel of the 

 Stone Dam col is about three miles. With the opening of the latter 

 channel the waters fell 400 feet, and tliis level, witli some down-cutting of 

 the outlet, endured for a long period. 



This ancient outlet channel is at the head of a short l)ranch of Marsh 

 creek, about four miles from Mapes station, on tlie J^uffalo and Susque- 

 hanna railroad. The locality is named after an al)andoned milldam of 

 stone in the vicinity. The channel is a remarkable rock-gorge, cut down 

 in purplish shales to almost the grade of the Genesee valley. Riding 

 from Mapes station to the water-parting the rise is almost imi)ercei)tible, 

 but Mr Pierce says there is a difference in altitude of 45 feet. The divide 

 is a swamp, filling the l)ottom of the narrow valley and extending over 

 one mile. Eastward to the Genesee and westward by the Honeoye creek 



