28 NEW YORK STATE MUSEUM 



later of the glacial streams here seems to have dropped its detritus 

 into the Warren flood. 



In this region, therefore, we find the critical relation of the ice 

 front to the changing lake levels; the lowering of the base level of 

 drainage from the Whittlesey to the Warren waters, or from 

 about 910 to about 860 feet. The Marilla delta is the most westerly- 

 delta built by glacial drainage close to the lake shore with a level 

 below the Whittlesey plane. 



The change in the level of the drainage is more abrupt than 

 would be expected. It is not supposed that the broad Lake 

 Whittlesey could fall suddenly to the Warren plane, but the ice 

 front seems to have held so steadily here that the relation of lake 

 level to inflowing streams changes abruptly, or within a short 

 distance. Two miles southwest of Marilla the extended East 

 Elma delta is over 900 feet altitude. At Marilla the delta is at 

 the Warren level, 860 feet. The channels of ice border drainage 

 I mile south of Marilla terminate at 900 to 940 feet. The channels 

 at and southwest of Marilla are down to 860 feet. There seems 

 no doubt that the higher channels debouched into Whittlesey 

 waters ; the lower into Warren waters. 



An unusual display of ice border drainage is seen on the four 

 north and south highways between the meridians of Marilla and 

 Alden. On the road through Williston not less than nine channels 

 are mapped, spaced through about 5 miles. The earliest and 

 highest channel that has been noted on the Williston meridian is 

 3 miles south of Williston, leading over to Buffalo creek at Wales 

 Center, with an altitude of iioo feet. The lowest channel is at 

 four-corners, 2 miles north of the village, where three primary 

 channels lie athwart the north and south road and unite into one 

 river course (the later of the two at Marilla) which carried the 

 waters from the Cayuga creek valley (the Cowlesville lake) over 

 to the Warren level at Marilla. The earliest flow through the 

 upper course of this channel may have helped to cut the cemetery 

 bluff at Marilla ; and the later flow contributed to the lower delta 

 terrace at Marilla in an embayment of Lake Warren. 



The earliest and highest channels in the territory included in this 

 chapter (between Buffalo and Cayuga creeks) lie east of the meridian 

 of Cowlesville, since the Cayuga creek flows northwest. The 

 highest channels actually seen and definitely mapped lie i mile 

 north of North Sheldon corners at 1400 feet altitude. A still 

 higher overflow should have occurred, somewhat under 1500 feet, 

 and scourways will probably be found J mile north of the corners. 



