188 
GEOLOGY OF THE FIRST DISTRICT. 
The general characters of the boulders on the west side of the Hudson valley above the 
Highlands, have been stated. On the east side, there is also a great variety. A smaller 
number of facts will be adduced on this side ; not for want of them, but the reader may think 
so many superfluous, as the general directions of thq^ transport of the drift of the Hudson 
valley and Long island- are undoubtedly nearly north and south in the former, and northwest 
and southeast on the latter. 
In the vicinity of Poughquaick, in Beekman, “ a large share of the boulders is of limestone, 
mixed with those of quartzose gneiss. Many of the limestone boulders are vesicular, from par¬ 
tial disintegration. After crossing Fishkill creek to the west, there was a change in the 
boulders and pebbles. The limestone boulders are darker colored, more siliceous, and are 
evidently from a different stratum.* The quartz boulders are also darker and more abundant, 
and bear a strong resemblance to those found in the vicinity of the ‘ primitive argillite.’ ”t 
On the range of hills between Fishkill and Sprout creeks in Lagrange, “ the boulders are 
of those rocks peculiar to the ‘ primitive argillite region; consisting principally of milky 
and brown quartz, with chlorite occasionally adhering.”^ 
Near Barnegat, about three-quarters of a mile north, near the shore of the Hudson, the 
quaternary yellow and blue clays occupy a small valley. In the lower part of the blue clay, 
pebbles and boulders of quartz and of grit rock of the Hudson slate series are imbedded, 
and they seem to have been deposited while the clay was also being deposited ; the boulders 
and pebbles are in many instances smooth and scratched, like those of the blue clay in Ohio 
and Michigan. 
On the mountains between Hurd’s corners in Pawlings, and Beekman, which are mostly 
mica slate and gneiss. Prof. Cassels observed a great number of granite boulders, and also 
on the east side of the Dover and Croton valley in Pawlings. 
In Stanford, south from Mount Stessing, are numerous boulders of granite and gneissoid 
rocks, like those of that mountain, and also a hard siliceous rock like granular quartz, and 
which is identical with a similar rock at the south end of the mountain overlying the primary 
rocks, and underlying the limestone of the valley of Wappinger’s creek (the Barnegat lime¬ 
stone, Newburgh limestone, and Calciferous sandstone of the Geological reports). This sili¬ 
ceous rock is believed to be the same as the Potsdam sandstone of Prof. Emmons. 
In Columbia county, the sides of the valley extending from Ancram through Copake and 
Hillsdale, are strewed with an abundance of boulders from the rocks of the neighboring moun¬ 
tains, which are mostly quartz and talcy slate containing veins of quartz ; and also with some 
boulders of limestone, and a dark siliceous highly indurated rock belonging to the Hudson 
slate, but almost resembling greenstone, and which is found in place in Austerlitz, Canaan, 
* Same as the Barnegat limestone or Calciferous sandstone, 
t Chloritic, and containing fragments of the slate, 
t Talcy, dark colored slate. 
^ Prof, hriggs’ Field Notes on the New-York Geological Survey. Both the rocks mentioned occur in place on the east side 
of that valley. 
