METAMORPHIC ROCKS. ’ 453 
of Verplanck’s point. It is supposed to be a displaced, outheaved mass from the preceding 
range. 
7. Another range extends up the valley of Peekskill creek from its mouth, and is a con¬ 
tinuation of that in Rockland county, at Tompkins and Marks’s quarries, associated with the 
same rocks. 
There are many smaller bodies of limestone, some of which may be parts of the above 
beds, as there are several lines of transverse stratification, and lateral heaves and faults, that, 
in some places, render the tracing of the continuity of the beds a matter of much difficulty, 
and requiring more time than was at my disposal. These beds above described have not all 
been traced out continuously, and there may be some error in some of them, and there may 
be more beds than have been indicated, but these bodies are the principal ones. 
Local details of the Limestone beds. 
A small quarry is opened in the white limestone on the farm of Elijah Martin, two and a 
half miles west-northwest of Whiteplains. Mr. Cassels estimates its surface width at one- 
eighth of a mile. It is associated with mica slate. It ranges a little east of north and west 
of south. 
About two and a half miles west of Whiteplains, the bed of limestone is exposed about 
one-fourth of a mile wide, according to Mr. Cassels ; and the range is the same as above, and the 
dip is at a high angle to the west. It is of a dark grey color, and contains pyrites. It disin¬ 
tegrates where exposed, into a brownish red calcareous sand, which covers the rock in many 
places. “ Black mica slate may be seen a few rods west of the limestone, dipping in the 
same direction; and a few rods east of the limestone, the same black mica slate may also 
be seen, having the same strike and dip.”* The same limestone was seen three miles south¬ 
west of Whiteplains. 
A quarry of limestone has been opened in Westchester township, about one-fourth of a mile 
north of the Harlem bridge. Its color varies from grey to white, and is more or less mixed 
with mica. Much of this rock would be mistaken for gneiss, without close examination. It 
dips W.N.W. about 80°, and the line of bearing is N. 25° E. The contact of the limestone 
with gneiss was observed on the east side of the quarry. 
The Westfarms marble quarry is about one and a half miles from Westfarms. Little is 
now done there, although the stone is of as good quality as is usual for this stone. Forty- 
thousand cubic feet of marble were quarried there in 1837. The proprietor receives six and 
a quarter cents rent per cubic foot of marble raised. Some large blocks have been quarried, 
and from appearances more may be procured with little labor. The value of such quarries 
may be estimated from the rent received by the proprietor, which, for forty thousand feet, 
the produce of last year, gives two thousand five hundred dollars for one year’s rent. The 
* Prof. Cassels’s Geological Notes of the New-York Survey, Vol. 7, p. 7. 
