686 GLACIAL FORMATIONS OF ERIE AND OHIO BASINS. 



from south of west to north of east. The southern range lies only 1 to 2 

 miles north of the inner border of the Alden moraine. The second range 

 lies 1 to 2 miles farther north. The second range crosses to the north side 

 of Tonawanda Creek near East Pembroke, while the south range lies south 

 of the creek all the way to the Batavia moraine. There is a short range of 

 knolls soiith of Indian Falls, which is fully 2 miles north of the second 

 range. A range west of East Pembroke is also somewhat distinct from the 

 second range, and trends from southwest to northeast. 



These ranges of knolls may find westward continuation toward Buffalo 

 along the Corniferous escarpment, there being a few drift knolls and short 

 ridges scattered along the base of the escarpment frofn Akron westward, 

 and a few knolls on the escarpment between Akron and Crittenden. These 

 knolls along the base of the escarpment may, however, be incident to the 

 retarding influence of the escarpment upon the ice movement, in which case 

 they may indicate nothing as to the position of the ice margin. 



RANGE IN ALTITUDE. 



The highest point in this system of knolls is in a gravel ridge on the 

 north side of Tonawanda Creek, about 2 miles northeast of East Pembroke, 

 which bears some resemblance to an esker. This ridge, as shown by the 

 Medina topographic sheet, rises above the l,UOO-foot contour. It is 75 to 

 100 feet higher than the majority of the knolls in that vicinity, and stands 

 130 feet above low ground within one-fourth of a mile to the east, north, or 

 west. The crests of the two ranges generally stand between 900 and 950 

 feet, while the low ground on their boi'ders is about 850 to 875 feet. 



TOPOGRAPHY. 



The south range of knolls is in places scarcely one-fourth of a mile in 

 Avidth, though the knolls rise 30 to 60 feet above bordering- plane tracts. 

 There are scattering knolls along the north border of this range which are 

 but 10 to 15 feet high. The range has, on the whole, greater continuity than 

 the one north of it, but is not so prominent. The north range contains 

 several knolls 75 feet or more in height and many are 40 to 50 feet. It is 

 so prominent that its course may be seen for several miles at a stretch. 

 Some of the knolls are sharp and conical; others are elongated, though 

 seldom to a greater length than one-fourth of a mile. The large knolls 

 carry hummocks on their slopes and also send out irregular spurs, which add 



