1082 NEW YORK STATE MUSEUM 



The collection was obtained from excavations made in deepen- 

 ing the Erie canal during the winter of 1897-98. The precise 

 locality begins at a point a few rods east of the Brighton- 

 Pittsford line in the latter township and extends southeast for 

 a distance of about 300 yards. Though the exposure did not at 

 any one point exceed 9 feet in hight, yet, owing to the dip of 

 the strata toward the east, higher levels were brought down to 

 view, so that the entire vertical section was about 16 feet. 



The rock is a soft shaly marlite, in layers of different colors, 

 often mottled, and interspersed with a few thin layers of very 

 hard, fine grained dolomite. 



The eurypterids are found in a rather fissile, very dark olive- 

 green to black shale, which, like the adjacent argillaceous 

 strata, rapidly disintegrates on exposure. 



The beds of this section in descending order are: 



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 mot- 



tlings 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 un- 



evenly; grading to olive-green shale in the 



upper part 10 



9 Dolomite like no. 2 10 



10 Black shale, with leaf of dolomite y 2 inch thick 



four inches from its base 1 2 



11 Dolomite like no. 2 2 



12 Soft, green, arenaceous mud-rock, occasionally be- 



coming shaly; the lowest exposed rock of the 



cut 1 8 



The eurypterid fauna occurs in the black shale, nos. 8 and 10 

 in the foregoing table. 



