$6 NEW YORK STATE MUSEUM 



close correspondence between the delta levels and the channels, 

 as there can be no question of their genetic relationship. 



The channels which carried the glacial flow eastward from the 

 Jamesville district over to the Limestone valley are quite as con- 

 spicuous and interesting as those just described. As shown by the 

 map there are a large number of distinct notches or gashes across 

 the steep scarp between Jamesville and Manlius, the higher ones 

 being in Marcellus shale with one lake and fossil cataract, Blue lake, 

 rivaling the Jamesville lake and amphitheater. The Blue lake 

 gorge leads north and joins the High Bridge channel, which is the 

 only channel extending directly and entirely across the land 

 between the two valleys. Three miles east of Jamesville and 2 

 miles southwest of Manlius is the head of an interesting ravine, 

 with a cataract cliff about 100 feet high and an amphitheater 

 about 50 rods across. The bottom of the ravine is a smooth meadow 

 with two levels. The upper level is about \ mile long, the surface 

 being a smooth floor of fine detritus. The lower end of this meadow 

 drops oft abruptly 20 feet to another meadow, about 20 rods wide 

 and \ mile long, opening to the valley of Limestone creek a mile 

 from Manlius village. 



The Blue lake channel heads at about 780 feet and was cut by 

 water in continuation of the flow of the earlier stage of the Reser- 

 voir channel. The flow through the Jamesville canyon was carried 

 eastward by the notches cut in the scarp northeast of Jamesville 

 and the earlier stage of the High Bridge gorge. The latter channel 

 is a direct continuation of the Railroad channel, and the altitudes 

 of the two channels are the same. However, since the Railroad 

 channel ends with a deep V-shaped gorge the later flow must 

 have found the eastward escape lower than by the High Bridge 

 channel and therefore poured northward down the Onondaga 

 valley, plowing away much of the earlier delta. This fact is evi_ 

 dent on a glance at the map which shows that the Railroad chan- 

 nel carried all the east-flowing glacial waters until the ice front 

 had receded 3 miles, or to the Syracuse outlet. 



The production of cataracts on the west side of each valley in 

 this region proves that the waters stood much lower in each valley, 

 successively, than in the next valley on the west. Such discord- 

 ance of the water level could not have existed if the ice front had 

 extended in an east and west direction across the ridges and val- 

 leys. Instead of that the ice front during its last stand in this 

 locality was part of a convexity or lobe which gave here a north- 



