442 H. L. FAIRCHILD — GLACIAL GENESEE LAKES. 



In the Kishawa valle}^ no measurements of this plane have been taken. 

 The prominent high i)lateaus about the head of the Dansville valley ^ 

 belong to the antecedent phase of the local lake and mark the earliest high 

 levels (see plate 21, figure 1), but the lower extensive plateaus about Poags 

 hole mark the latest levels of the water; these are as low as 1,220 feet, or 

 only 10 feet over the present channel. A correction of the datum in the 

 Dansville valley makes the summit plateau on the east side of Poags 

 Hole, or west of the Central New York and Western railroad station, 1,262 

 feet, and the highest terraces near Conesus fall into levels under 1,200 

 feet, the latter consequently belonging to the waters of the next stage, t 



SEVENTH STAGE: WARREN TRIBUTARY LAKE. 



Outlet. — Tlie outlet was across the western divide into lake Warren. 



This stage of the glacial Genesee waters is at the time of this writing 

 not entirely certain in all features, partl}^ on account of the indefinite 

 character of the phenomena and i^artly for lack of detailed study of the 

 area involved. 



The western divide between the Genesee and the Tonawanda drainage 

 is a broad, irregular land mass which declines northward from altitude 

 of about 1,400 feet near Warsaw to about 900 feet near Batavia. As the 

 ice-sheet was removed from this north ward -sloping divide at an altitude 

 of about 1,200 feet, the glacial waters began to spill over westward into 

 other waters tributary to lake Warren. The sixth stage in this history 

 did not come to an abrupt end by the sudden opening of a single outlet 

 far below the height of the Burns-Arkport outlet, but terminated gradu- 

 ally by the uncovering of the irregular dividing ridge above described. 

 The earliest overflow seems to have occurred at a point a])()ut two miles 

 south of tlie village of Bethany, where a narrow scourway of small ca- 

 pacity is seen crossing the divide at an altitude by aneriod of al)out 1,200 

 feet. Somewhat larger scourwa3''s at slightly lower altitude are found 

 one-half mile south of the village, and still larger ones one-half mile north 

 of the village at altitude of about 1,100 feet, 'i'he largest water-course 

 observed is some two miles north of Bethany and directly west of East 

 Bethany, where a well defined channel over one-fourth mile wide is cut 

 down to rock. This sli allow pass is traversed by the Delaware, Lacka- 

 wanna and Western railroad, which to secure easier grade has cut 10 feet 

 into the decomposing shales. The present water-parting is about two 

 miles west of East Bethany station, where the rock-sill of the waste-weir 

 has an altitude of about 1,030 feet, or 180 feet lower than the outlet of 

 the sixth stage waters. From this scourway no single large channel is 



* Vol. 6 of this Bulletin, pp. 358-360. 



f Tliis is a correclioa of the altitude given in the former paper, vol. 6 of this Bulletin, p. 36L 



