190 ROCHESTER ACADEMY OF SCIENCE. [J^n. 9, 



ESKERS IN PiTTSFORD. 



From 2J^ to 3 miles southeast of Brighton, the New York Central 

 railroad makes a long cut through the northern end of a second esker 

 series, which takes a course approximately at right angles with that 

 of the Pinnacle hills. Beginning close south of Allen's creek, in the 

 southwest corner of Penfield township, this belt of kames and eskers 

 runs south-southeasterly through the east half of Pittsford and about 

 a mile into the southwestern corner of Perinton, terminating in a sand 

 plateau, which abuts upon the western base of the prominent Turk's 

 hill range of drumloid drift. The length of this Pittsford esker series 

 is about seven miles. 



In its northern third, extending from Allen's creek southward to 

 about a mile east of Pittsford village, the width of this belt varies 

 mainly from a half mile to fully one mile, and it consists of a princi- 

 pal broad north to south esker ridge, becoming narrower and inter- 

 rupted southward, with a considerable lateral expansion, especially on 

 the east, in kames, or short ridges, mounds and hillocks, all being 

 composed of sand and gravel, with infrequent enclosed boulders. The 

 cut for the railroad is about a half mile long and 50 feet deep. Its 

 greater part is yellow sand, nearly horizontal in stratification, except- 

 ing at the margins, where the bedding is more irregular, prevailingly 

 dipping downward like the surface slopes. In this sand are occa- 

 sional thin gravelly layers, but these are nowhere conspicuous. Very 

 rare embedded boulders were seen. Only two, which were respect- 

 ively about 3 and 5 feet in diameter, were exposed in the section at 

 the time of my visit, and scarcely a half dozen in total lie at the foot 

 of the banks on both sides of the railroad. The basal part of this 

 section, however, for about an eighth of a mile west from its center, 

 consists of coarse gray gravel, containing very closely packed gravel 

 stones and cobbles up to 6 or 8 inches in diameter, but no larger 

 boulders. On the north side of the excavation the gravel reaches to 

 a height of about 20 feet above the track, and displays a very distinct 

 anticlinal stratification. 



About i^ miles southeast from this railroad cut, a small excava- 

 tion for the passage of a north to south road through a kame deposit, 

 chiefly of sand, near the east line of Pittsford and the east border of 

 the esker and kame belt, reveals a boulder 3>^ feet in diameter, 

 embedded 10 feet below the surface. Beneath and above the boulder, 

 the stratification of the sand and gravel is contorted and curved, in 

 conformability with the outline of the rock mass. 



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