282 
GEOLOGY OP THE FIRST DISTRICT. 
the point of contact, is much modified in texture, like that described between the New- 
Jersey line and the mouth of Tappan creek. 
Two places on the shore, near Verdrietige hook, shewed appearances of enormous dykes 
of trap penetrating through the sandstone, from two hundred to six hundred feet wide. They 
are either dykes, or else double faults concur to produce the same appearances; for the trap 
breaks suddenly from the sandstone above, and comes down to the water on both sides, as 
represented on Plate 5, fig. 4. 
Near the same place, or within a mile south, trap has penetrated laterally between the 
sandstone, and has altered very much the characters of the rock. Some of the sandstone is 
almost as hard and compact as jasper; some is purplish, red, and very much indurated; 
some is grey, and filled with vesicular cavities ; and the trap itself, in some places, is com¬ 
posed in part of the materials of the sandstone. Some of the trap is amygdaloidal, and con¬ 
tains an abundance of chlorophaeite. The layer of trap, and an adjoining one of greyish 
sandstone, are loaded with scales, and small masses of micaceous and specular oxide of 
iron. 
At another locality about two miles below Haverstraw, on the shore, about a quarter of a 
mile below a landing, a trap dyke of one foot wide, a fault, and a layer of trap intruded be¬ 
tween the strata, were seen. Plate 5, fig. 5, illustrates the phenomena observed at this place. 
The contact of the overlying semi-columnar trap with the sandstone was not seen, as it 
was concealed by a slope of debris, which extended from the base of the escarpment to near 
where the sandstone was exposed to view on the shore. The upper mass may not be con¬ 
nected with this small dyke, though it is probable. The sandstone next the trap of the dyke, 
is almost like jasper in some places, and blends off into perfect sandstone ; in others the rock 
is porous, as if heated so as to extricate gaseous matter, and blow up bubbles in the half 
melted rock. 
In the town of Ramapo, near the southern extremity of the western hook of this trap 
range, traces of copper ore were observed in the trap by the road-side, between Ladenton 
and the outlet of the valley of the Ramapo river, on Smith’s clove, from the Highland moun¬ 
tains. On some of the masses of trap, a siliceous coating was covered and colored by the 
green carbonate and the red oxide of copper. They were traced to their origin near by, 
where the rock in place shewed seams and cracks presenting similar appearances in abun¬ 
dance, but no veins could be traced. Veins of infiltrated or injected siliceous matter, a quarter 
of an inch thick, were sometimes seen. 
A single nodule of most beautiful agate was found among the debris of the trap ridge, at 
the above locality. It was coated with the red oxide of copper. The trap was of the com¬ 
pact variety, 
Mr. Cassels, one of the assistants, observed one locality where the trap rock next the sand¬ 
stone had a distinct columnar structure. The locality is stated by Mr. C. to be three miles a 
little west of north of the New city, in Clarkstown, near one of the places where Levi Smith 
had quarried a set of furnace hearth-stones, a quarter of a mile west of Richard Coe’s quarry.. 
The sandstone is grey. 
