Page:The Habitat of the Eurypterida.djvu/108

4. THE PITTSFORD SHALE

This formation is typically developed in the western part of central New York where, in the town of Pittsford, Monroe county, the following section is shown (Sarle, 240, 1082):

		FEET	INCHES
1.	Red shale	6
2.	Light gray, compact, fine-grained, dolomite, with imperfect conchoidal fracture, weathering light brown to cream color		10
3.	Soft, gritty mud-rock, purple with bright red mottlings	1	3
4.	Dolomite like No. 2		4
5.	Purple shale with red mottlings	1	11
6.	Green shale	1	2
7.	Thin layer dolomite like No. 2		4
8.	Black shale, very compact, the base splitting unevenly; grading to olive-green shale in the upper part		10
9.	Dolomite like no. 2		10
10.	Black shale, with leaf of dolomite ${\tfrac {1}{2}}$ inch thick four inches from its base	1	2
11.	Dolomite like no. 2		2
12.	Soft, green, arenaceous mud-rock, occasionally becoming shaly; the lowest exposed rock of the cut	1	8

The eurypterid fauna occurs in the black shales, Nos. 8 and 10.

A more complete section is shown in the wells of the region, from which the exact location of the fossiliferous black shale beds is ascertainable. The section carries the series clown to the Lockport-Guelph horizon.

Salinan

		FEET	INCHES
1.	Red shale or marlite	10
2.	Hard, fine grained, yellowish, dolomite, having an imperfect conchoidal fracture	2
3.	Red shale	1
4.	Break estimated at	3
5.	Dolomite like No. 2	3
6.	Green shale or marlite	4
7.	Red shale	1	8
8.	Break estimated at about	2
9.	Green shale	2	5