J. D. Dana— Origin of the Rocks of the Cortlandt Series. 118 
plastic and have “a injected into fissures so as to produce 
ike-like veins, and might retain internal marks of their former 
mobility in broken cr poser if not in other evidences of 
wing. 
As to the centers of eruption, it is to be noted that the occur- 
granite, may be an indication that one of them was located in 
what is now the river channel off the Verplanck shores. (See 
map, p. 107). 
Since my former account of Stony Point was published I 
have made a further examination of the region with reference 
to this and other points. The chief facts as to the distribution 
and positions of the rocks are given in the preceding map.* The 
mica schist of the northwest and south sides of the Point join 
over the southwestern side; and the strike and dip show that 
there is here one stratum in a synclinal fold. Overlying the 
schist occurs the soda-granite in two areas; and next comes 
the chrysolitie rocks. The chrysolitic rocks thus occupy ap- 
proximately the middle setts of the synclinal.t 
e soda-granite is mostly of the coarsely’ crystalline, light- 
calored kind, looking like ordinary granite, but, in the vicinity 
of the schist, in some parts, a fine-grained variety, gray to black 
in color, occurs; and the fine variety sometimes intersects the 
coarse, or the reverse, as if in veins. In one case, near the 
*This map is based on a survey of the Point by Mr. L. Wilson, Principal of 
the mt institute, Haverstraw, N. Y., obligingly made at the request of 
+In + Tee ormer account of the Point, I 0 
stratgrapically underlies the mica Sante it dipping aedor it, ‘as at Origers 
and ination confirms this conclusion. It is therefore a 
_It isa fact of interest that at Cruger’s this overlying schist is oka ey just 
like the overlying gueiss adjoining the limestone of New York Island. The 
fibrolitic gneiss of 123d street, on the corner of Tesxington babes ie put a few 
near the junction with the ravaeliie rock, occurs a thick stratum of. sieonauas 
: t 3 
off to the northward with a nearly vertical dip (70°-80° N.) and a strike of N. 
70° EK. The limestone is situated somewhat like the small beds in the interior of 
the the oat peninsula, and as near to the massive rock; the latter = proved 
In one case to be conformable to eras of bedding in the selghia ring noryte ; 
and in ustbet case, to the mica schist; but the relations of this Stony Point bed 
The Tompkins Cove limestone, on the shore just north of the limits of the 
above map contains many veins of quartz, and assays made fg the proprietor, 
Mr. Edward A. Swain, have proved that the quartz is aurifero 
