696 GLACIAL FORMATIONS OF ERIE AND OHIO BASINS. 



Towiisliip. This belt of knolls is situated immediately noi'tli of the iiortli 

 border of the drmnlin belt from near the "New Guinea Settlement" east- 

 ward to the Grenesee River, and presents a strikingly different topography, 

 as may be seen by the topographic sheets and to some extent in PI III. 

 The number of knolls is greater than in the district to the north, though the 

 latter is by no means free from them. 



RANGE IN ALTITUDE. 



The principal variation in altitude is made in rising from the plain 

 north of the Niagara escarpment up to the brow, the altitude near the base 

 being only 400 feet and on the brow about 630 feet. The level of the base 

 of the drift ridges and knolls from the escarpment eastward to Oak Orchard 

 Creek falls between 620 and 650 feet, while the crests of the ridges range 

 from about 630 feet up to 700 feet, the highest points being near West 

 Shelby. From West Shelby to East Shelby the crest stands generally 

 between 65.0 and 675 feet, but knolls on a sjDur north of the main ridge near 

 the Ross geodetic station rise above 700 feet. From East Shelby to West 

 Barre the crest is mainly between the 660- and 680-foot contours, but a 

 point on an esker at the Pusel geodetic station, a mile northwest of West 

 Barre, reaches 737 feet. This appears to be the highest point in Orleans 

 County. From West Barre to South Barre the crests of ridges range 

 between 650 and 700 feet, the lowest ridges being situated in the edge of 

 Oak Orchard Swamp. At the border of the sharp drift knolls in the New 

 Guinea Settlement, the swamp stands just below the 640-foot contour, while 

 some of the knolls rise above the 700-foot contour. From this group of 

 knolls eastward to western Monroe County there is but little descent, the 

 altitude being generally between 620 and 650 feet; but from the meridian 

 of Church ville to the Genesee River, a distance of about 12 miles, there is 

 a descent of almost 100 feet, the altitude on the border of the Genesee 

 being but little above the 520-foot contour. 



. Particular attention is called to the range in altitude because the narrow 

 ridge leading westward from West Barre has been considered a beach of 

 Lake Ontario by many of the residents. The form and structure in places 

 seem to sustain that interpretation. This is especially true of the part 

 between West Barre and West Shelby; but in this part of the ridge there 

 are oscillations of 30 or 40 feet in the level of the crest within a distance of 



