170 
GEOLOGY OF THE FIRST DISTRICT. 
point and other places. Some of the blocks weigh from one hundred to five hundred tons. 
Boulders, blocks and large pebbles of red sandstone, like those of New-Haven and Cheshire 
in Connecticut, occur here in some abundance. A few blocks only of conglomerate, of the 
red sandstone formation, were seen. 
On the north shore opposite Greenport in Southold, the clilf had been washed away at its 
base, at the time of my visit, so as to expose its stratification. The base of the cliff consists 
of sand, gravel and pebbles, horizontally stratified. These materials are variously colored, 
and are overlaid by the greenish and bluish loamy stratum containing the blocks and boulders. 
In Riverhead township, from Roanoke point for two or three miles east, the shore is skirted by 
a high cliff composed principally of clay and sand, the clay forming a layer above the boulder 
stratum, as well as in the strata below. The land-slides of this part of the coast have already 
been described.* * * § Boulders are seen in the greatest profusion along the shore. The boulders 
and pebbles lie at a depth of twenty or thirty feet below the surface of the earth at this place, 
and for a mile east. The boulders, blocks and pebbles seem to be collected in groups or 
nests in particular localities here, as at and near Brown’s point, and Horton’s point, etc. 
At Roanoke point, and for three or four miles east, a large proportion of the blocks, boul¬ 
ders and pebbles are of red sandstone and trap rocks, like those of New-Haven and that vici¬ 
nity. In some places these rocks form one-third of the mass of boulders, blocks and pebbles. 
The sandstone is of the coarse, fine and fissile varieties, and often quite micaceous. The trap 
is greenish, compact, vesicular and amygdaloidal. 
At Hudson’s point, three beds of clay are visible in the cliff; the upper greyish, the middle 
bluish and containing pebbles and some boulders, the lower brownish with a tinge of red, like 
that in the same geological position at Brown’s point, Oysterpond point, etc,, and belonging 
to the tertiary. These three strata at Hudson’s point display a thickness of from sixty to one 
hundred feet.f 
In Brookhaven township,! a block of gneiss was seen a few rods from the road, on the 
north side, about a mile east of Coram. It is possible that it may be rock in place, as it lies 
on the ridge, is stratified, and its line of bearing is about N.N.E. and dip 60° to 80° W.S.W., 
conforming in direction and dip to those in that direction in Connecticut; but it is scarcely 
probable that it is in place, as rock has not been found distinctly in place on the island, except 
near Hurlgate, and it is not larger than a great number of the blocks overlying the tertiary 
sands and clays of Long island. The part above ground would weigh perhaps two hundred 
or three hundred tons. Pebbles were abundant on this ridge, but no other rocks were seen.§ 
Boulders are abundant on the hills south of the road between Coram and West Middle island. 
* Vide page 33 of this volume. 
t In the northwest part of Riverhead near Wading river, boulders were observed in abundance in the hills. They were mostly 
granitic, with some of gneiss and greenstone. 
t About three miles east of Moriches, the fragments of a large boulder were seen by the road-side. It was a reddish contorted 
gneiss, precisely similar in appearance to a granitic or gneissoid rock that abounds between Groton and Norwich, and in New- 
London and Montville in Connecticut. The rock is not fissile, but the mica and other materials are arranged in curved and con¬ 
torted lines and layers. 
§ The ridge was mostly covered with trees and brush-wood at that time. 
