1894. | NEW YORK ACADEMY OF SCIENCES. 221 
and extend three hundred feet down stream. The stone is 
white, fine grained, purely siliceous, and contains minute black 
shells of Obolella prima. Below the mill on the east side the 
quartzite rises in a cliff thirty feet high beneath the drift, and 
runs at the same height; across the river diagonally to thenorth- 
west, the fifty foot cliff directly opposite being norite. The re- 
appearance of the Potsdam is at 179 on the map, in the bed of 
a small brook, which joins the river just north of the township 
boundary. The exposure is on the road side above the river. 
This quartzite is much coarser than at other points, and is like 
an odlite with a ferruginous cement. It dips 80° E., strike N. 44° 
E. The norite, here very gneissic, appears 30 feet above the 
quartzite on each side of the brook valley. Below the brick 
church. at the south end of Willsboro’ main street, ledges of 
Potsdam appear in the bed of the river, extending 20-30 feet, 
dipping 80° W., strike N. 20° E., while much higher up on the 
north side of the road, east of the church, what appears to be 
Calciferous occurs in a field at 196 of the map. Rock similar to 
the latter again outcrops on the same road, nearer Essex, and 
finally at the bend of the river, just below the pulp-mills (185 on 
the map), in an exposure ten feet high. 
CALCIFEROUS. 
The localities of the Calciferous are enumerated above, on ac- 
count of its close alliance with the Potsdam. It is difficult to 
identify with certainty. The only fossils found were those of 
gasteropod shells, in ledges beneath the water in the Boquet 
River, at 182 on the map. These shells were about an inch in 
diameter, with ridged coils, similar to Ophileta uniangulata, Hall. 
Apparently identical forms are figured by Whitfield* and 
ascribed to Ophileta complanata, Vanuxem. 
The rock is high siliceous and sandy, of a light gray color, 
often with lighter streaks. On one hand it resembles the Pots- 
dam, on the other the Chazy. 
CHAZY. 
The Chazy formation occurs on the southern third of Wills- 
boro’ Point, along both shores, and doubtless continues under 
the drift-covered portion, for it reappears at the head of Wills- 
boro’ Bay. 
*R, P. WHITFIELD: Observations on some imperfectly known fossils from the 
Calciferous sandrock of Lake Champlain. Bull. Am, Mus, Nat. Hist, Il.: 2 
(March, 1:89). 
