DRUMLINS OF CENTRAL WESTERN NEW YORK 425 



in such case) but a belt further iceward, the rivers truncating the 

 thinner border of the ice sheet. 



Moraine belts like the Auburn and Seneca Falls moraine represent 

 only the superglacial and higher englacial drift, carried to and 

 passively dropped at the extreme margin, while, pari passu, the 

 drumlins were forming beneath the ice in the rear of the moraine, 

 from the subglacial (and perhaps the lower englacial) drift. 



When recession of the ice front again occurred, either by increased 

 melting or by diminished ice movement, the superior drift was 

 quietly lowered on the drumlin territory, falling chiefly in the hol- 

 lows between them. Not infrequently we find a patch of irregular 

 surface among the drumlins which can readily be discriminated and 

 mapped as moraine, and rarely this may obscure the half buried 

 drumlins {^see p. 41 2J as in the Junius kame area. Sometimes the vol- 

 ume of moraine drift increases to the north and is so distributed as to 

 give a decided morainal surface among the northern drumlins, as in 

 the Walworth district [pi. 15]; or else the next succeeding moraine 

 on the north laps on to the north edge of the drumlin belt, as in the 

 Oswego district [pi. 6]. 



At the termination of heavy lines of glacial drainage, during both 

 the active and the stagnant episodes, heavy deposits of water-laid 

 drift (kame moraines) accumulated, as the Junius, Victor, Ironde- 

 quoit valley, Mendon, and other kame areas. 



Theoretically the moraines should be weak where the drift was 

 left in drumlin form, and the facts seem in accord. In the stretch 

 from Batavia to Syracuse the moraine belts are weak, though a few 

 kame areas are strong. 



Special features 



Syracuse island masses. These remarkable groups are partly 

 shown in plates 9 and 10 and are fully shown on the Syracuse and 

 Baldwinsville sheets. They are partly bounded by river channels of 

 the latest glacial drainage cut in Salina shales. North of Warners 

 [pi. 9] is an example of such drumlin massing not surrounded by 

 river valleys. In the more striking of these groups there is a cumu- 

 lation or increase of hight toward the center which is a peculiar 

 feature. If these drumlin masses have a core of rock reaching 

 above the Salina shales, which form their base up to 500 feet or 

 more, it has not been found, though it is not improbable for the 

 more northerly groups. 



