1888. | NEW YORK ACADEMY OF SCIENCES. 229 
change. The orthoclase crystals were of large size, some six by 
four inches. Crystals of less size appear in a porphyritic rock 
on the east bank of the Harlem River above McComb’s bridge 
(L. Winslow). 
Remarkably fine groups of modified crystals coated with albite 
(G. J. Brush) were secured at 96th street near Third avenue. 
Necronite (fetid feldspar), of a bluish white color, in tabular 
masses in limestone, Thompson’s quarry, Kingsbridge. 
Adularia. Corlear’s Hook (I. C.). In serrated columns of 
aggregated crystals, Fourth avenue and 90th street. 
Glassy feldspar (G. J. Brush). 57th street and Sixth and 
Seventh avenues. In rocks at Bellevue (I. C.). In quartz veins 
in limestone at Corlear’s Hook (Rob.) (I. C.). 
Kaolin. Old road three mile stone (I. C.). Deposit of three 
colors, red, yellow, white, 70th street and Fourth avenue. Vein 
in Central Park and vicinity, Eighth avenue and 104th street. 
Anhydrous—Subsilicates. 
Tourmaline. In granite. McGowan’s Pass (I. Cozzens). 
Good specimens of the black variety set in pink orthoclase, 
80th street and Fourth avenue. 
Large masses showing no crystal faces, and readily crumbling 
into what might be taken for black sand, Morningside Park, 
122d street. 
Brilliant prisms of moderate size set in a bluish oligoclase. 
Also crystals slightly iridescent, Tenth avenue and 172d street. 
Small, but brilliant doubly terminated crystals, associated 
with clear pink garnets, affording an interesting exhibit under 
a magnifying giass, First avenue and 45th street. 
Massive tourmaline, with pyrite, filling fissures, Jumel 
grounds, Washington Heights, 
Perhaps the most remarkable deposit of tourmalines in 
the island, on record, was discovered by the author in the year 
1885, in a vein of gray quartz traversing gneiss, parallel to 
the stilbite veins near the Fourth avenue tunnel, above 96th 
street. Many of the finest crystals were obtained by fractur- 
ing the quartz, which yielded readily to the chisel. Nearly 
twenty fine terminated crystals were among the number obtained 
at this point. The largest crystal was 5 inches in length, 14 
to 14 in. in diameter, with good terminal planes. 
With the tourmalines appeared the choice garnets above 
alluded to. Other minerals were green mica, sericite (?) 
smoky quartz, epidote, albite, and a very red orthoclase. 
