PLEISTOCENE HISTORY OF THE GENESEE VALLEY 51 



Later stages 



Other stages now recognized are those of the Scottsville lake; 

 Lake Iroquois; Gilbert gulf (sea level waters) ; and Lake Ontario. 

 As water planes they lie inferior to the valley bottom at Mount 

 Morris and therefore do not properly appear in this connection. 



Epitome of the history 



Stage 4 Belfast-Fillmore lake. Outlet at Cuba ; 1496 feet. Port- 

 age moraine formed. 



Stage 5 Portage-Nunda lake. Outlet at Swains ; 1320 feet. Erie 

 viaduct terraces formed. 



Stage 6 Dansville lake. Outlet at Burns; 1210 feet. Portage- 

 ville morainal lake and beginning of the Portage 

 canyon. Delta terraces at Glen Iris and mouth of 

 Wolf creek. 



Stage 7 Mount Morris-Geneseo lake. Outlets at Linden-Beth- 

 any; 1200-1000 feet. Delta terraces about the lower 

 falls. 



Stage 8 Lake Hall. Outlets at Batavia;. 1000-900 feet. Ter- 

 races east of Bishop Corners ; Nunda plain. 



Stage 9 Lake VanuxeuL Outlets at Syracuse ; 900 and declin- 

 ing. St Helena-Gibsonville morainal lake and be- 

 ginning of the " High Banks " canyon. Tuscarora 

 morainal lake and beginning of the Sonyea ravine. 

 Upper terraces on Mount Morris delta. 



Stage 10 Avon lake. Outlets at Honeoye Falls-Rush ; 700-580 

 feet. Filling in Dansville-Avon valley. 



Stage 1 1 Second Lake Vanuxem. Outlets at Syracuse ; 700 feet 

 and rising. 



Stage 12 Lake Warren. Outlet via Chicago to Mississippi ; about 

 840 feet on the Mount Morris parallel. 



Stage 13 Lake Dana. CHitlet toward the Mohawk-Hudson; about 

 660 feet on the Mount Morris parallel. 



Canyons and cataracts 



The Portage canyon was cut by the outflow of the morainal lake 

 held in the valley above Portageville, the earlier flow being into the 

 glacial waters of stages 6-8, described above, and the later flow 

 into the St Helena morainal lake. 



The ravine and cataracts were not produced by free and uninter- 

 rupted flow of the river, with deepening of the whole ravine from 



