440 H. L. FAIRCHILD — GLACIAL GENICSEE LAKES. 



southeast of Belfast, 1,375 (aneroid) ; east of Orainel, 1,325 (anei'oid) ; 

 Caneadea, 1,343 (aneroid), 1,356 to 1,370 (spiritdevel) ; Fillmore, 1,344 

 to 1,370 (spirit-level) ; Portage, many points accuratel}'' measured, rang- 

 ing from 1,322 to 1,360. At Portageville.we know the exact height of 

 the plateaus. The Erie railroad passes over the scoured gravel plains at 

 Dal ton station, 1,330, and at Hunts station, 1,333, and at Portage station 

 has cut into a broad, fiat, gravel plateau 10 to 12 feet. The verified alti- 

 tude of the Erie trestle over the Genesee is 1,314 feet. The station is one 

 foot lower and the fine erosion plane at the .station is 1,323 to 1,325 feet. 

 By hand level and aneroid the numerous terraces around and east of 

 Portageville are made, as given above, 1,322 to 1,360 feet. West of the 

 village one shoreline bench, which probably marks the highest water 

 surface, is judged to be about 1,370 feet. The gravel ])lateaus cast of 

 Portageville are the leveled moraine or kame drift which ])locked the 

 old valley and diverted the river. With the first uncovering by the ice 

 the ])onded waters swept over this drift to reach the Nunda valley and 

 the Swains channel. A well defined scourwa}^ is seen on the highway 

 toward Hunts, with altitude 1,340 to 1,350 (aneroid). Later the waters 

 esca])ed over the lower ground north of Portageville, but the}'' did not fall 

 much below this level during the fifth stage, as the bottom of the present 

 Swains divide is 1,320 feet. 



At Angelica a delta was measured by aneroid from uncertain datum 

 as 1,435 feet, and east of Belfast are terraces, by aneroid, 1,430 to 1,450 

 feet. These do not correlate with the summit levels of either the fourth 

 or fifth stages, l^ut can ))c i)roperly regarded as marking a pause in the 

 subsiding waters. These are the only measurements made in the whole 

 valley which do not accord with an outlet plane. 



SIXTH STAGE: DANSVILLE LAKE. 



Oatlet. — The outlet was ])y middle Canaseraga gorge (Poags Hole), past 

 Burns and Hornellsville, to Canisteo creek, Chemung and Susquehanna 

 rivers (see plate 20, figure 2). 



The Burns- Arkport channel is the grandest of the abandoned water- 

 courses. Its effective life was probably shorter than some others described 

 above, but it carried a much greater volume of glacial water. The chan- 

 nel is about three-fourths of a mile wide, usually with drift banks, and 

 extends from the edge of the Poags Hole gorge, one and one-half miles 

 east of Canaseraga, past Burns and Arkport to Hornellsville, a distance 

 of twelve miles. Its fall in that distance is about 50 feet, but four-fifths 

 of this fall is in the last six miles. Between Burns and Arkport, three 

 miles, there is a fall of only three to five feet. Below Burns the valley 

 bottom is comparatively smooth, but above Burns, toward and at the 



