90 ROCHESTER ACADEMY OK SCIENCE. [.Ull. II, 



DESr.RlPTION OF 

 SAMPLE. 



Dark gray to bluish-gray argillaceous shale, non-cal- 



careous. (') 

 Red argillaceous and finely arenaceous chips. Medina. 

 Pure cjuartz sandstone, slight reddish tint ; 70' in 



thickness. 

 Dark red (chocolate) finely arenaceous chips. 

 About the same as Xo. 21. Bottom of well still in the 



Medina. 



Diagrammatic Section of the Batavia Well, at Batavia, 



New York. , 



Altitude 889' A. T. 



DEPTH. ^:^Esi\' KIND OF KOCK. 



40 



250 



40' Drift. 



60' Marcellus. 



Upper Helderberg. 

 Lower Helderbera:. 



o .V ' 1 1. . /: ' (Onondaga 



o About IS rock salt at 600 . - ^ 



750' ? Top of Niagara limestone. 



U-) Niagara. 



oco' Clinton (?). 



100' Probably mostly Medina, ('j 



too' Medina. 



Salt group. 



Bottom of well in Medina. 



In the summer of 1883 a well was drilled at Brockport, about 

 16^ miles east of north from LeRoy, and an account of this well 

 together with some samples was furnished by Mr. John H. Kingsbury. 



(i.) It is very difficult to decide whether this sample ought to be referred to the Niagara or 

 Clinton shale. Prof. Hall in 1852 called attention to the similarity of the lithologic characters of 

 these two groups in western New York, when he wrote: "The lithologic characters of the Clinton 

 and Niagara gnjups are so similar that they could well be united " (Geol. Surv. N. Y., Palaeontology, 

 Vol. II, p. 1071. But from a comparison of other well records and samples it is probable that No. 18 

 is from near the bottom of the Clinton. 



(2.) Sample No. 18 from 1000' is probably from near the base of the Clinton. The next sample 

 No. 19 from noo' is .Medina and probably most of the 100' between samples Nos. 18 and 19 belongs to 

 the Medina, which would give it a thickness of at least nearly 1000' in ihis well. 



