Geological Survey of the State of New York. 101 
on the west, and between mounts Adam and Eve. It contains 
beds of granite, quartz, hornblende, and augite rock, and is unstra- 
tified. ‘The minerals found in this are similar to those enumera- 
ted above, and they are among the riches of American cabinets, 
The Island of New York, as described by Dr. Gale, contains 
elevated ranges of granite and gneiss with imbedded rocks, a lim- 
ited range of limestone on the north, while the southern portion 
is covered with “ from ten to eighty feet of diluvium, resting on 
the same or greater thickness of alluvial or tertiary sands, which 
last are highly stratified and even exhibit the appearance of rip- 
ples as from the retiring waves of the ocean.” yd 
The most interesting portion of the report is that describing the 
bowlders and diluvial scratches. The bowlders are found in the 
greatest profusion and variety, and consist of greenstone in abun- 
dance—a rock that is not found in place on the island, nor nearer 
than the Palisades of New Jersey on the west, or on the east than 
Southbury, Conn., and the ranges of Connecticut River valley 
that terminate at New Haven. There can be little doubt that 
they came from New Jersey, in accordance with the general evi- 
dence of a current from the N. W. to the S. E., and yet although 
they have passed but this short distance, they are always rounded 
and covered all over with grooves and scratches. They are from 
ten to fifteen feet in diameter. In many parts of the city they 
have been removed by the process of grading the streets ; but in 
the front of Brooklyn heights, they may be seen in great num- 
bers, when excavations are made for erecting buildings. Others 
ane pf. 3 os setae 0) 
Red sandstone, a rock not found in the island, but limited to 
the same localities above named, underlying the trap. ee 
Serpentine, of, Hoboken, particularly in the south part, and at 
Corlaer’s Hook and Brooklyn. = ; : 
While limestone, as from Kingsbridge. : 
- Granite and gneiss, as abundant as greenstone, in every por- 
tion except the north extremity of the island. Those from ten to 
twelve feet in diameter are common, and one of granite, eleven 
feet diameter, “near Manhattanville, on the Bloomingdale road, 
tests on the gneiss,” which is covered with diluvial grooves, and 
avery large one, three inches deep and eighteen inches wide, be- 
tween the road and the bowlder, and terminating at the bowlder, 
seems to have been caused by the movement of this huge mass,” 
