METAMORPHIC ROCKS. 
455 
white and grey, and not easily disintegrated, and would, it is supposed by Mr. Cassels, make 
a good marble. The rock is stratified and somewhat contorted. 
Granular limestone occurs four miles northeast of Singsing, at Sarties’ hotel, where it was 
observed by Prof. Cassels. He did not note its strike or dip. Not far from the same place, I 
observed the white and grey limestone, ranging N. 60° E., and dipping north-northwest about 
forty-five degrees. It is exposed in several places in the vicinity of the Croton aqueduct, within 
one mile and a half of the dam. Limestone was also seen about two and a half miles from 
Singsing, near Mud millpond ; and south two or three miles from this place, it is presumed 
there is limestone (although it was not seen), as there is said to be a cave. The locality of 
the cave is said to be near Pleasantville, about on the line between Mount-Pleasant and 
Newcastle townships. 
At Singsing, the limestone is extensively quarried on the State farm, by the convicts in the 
State Prison. Almost all the limestone of these quarries crumbles by long exposure to the 
action of the weather ; but when kept dry, it is said to be a durable stone. Near the surface 
of the earth this rock is a perfect dolomite, covered by calcareous sand from the crumbling 
rock. Much of the rock in the spoil-banks that had been removed from the top of the quarries 
was so friable that it could be crushed to sand by pressure in the hands At a greater depth 
in the quarries, the rock is sound, crystalline, hard and tough. The bluish marbles seem the 
most durable, though all of them crumble by long exposure. This stone is extensively used 
as a building material, but in many instances it has already begun to crumble away. Examples 
may be seen in the stones at the bottom of the iron railing around the Capitol square, and the 
Albany Academy square, in Albany. Many blocks of this rock were brought to Albany for 
the construction of the New-State Hall, that were already crumbling ; but whether they were 
put in the structure, or rejected by the builders as they ought to have been, I do not know.* 
Lime is made from this limestone at the quarries, not only for consumption at the prison, 
but for sale. Large qualities of the stone are sold for the New-Jersey limekilns, where it is 
burnt with dust anthracite coal for manure. 
This stone is also used as a flux in the Coldspring furnace. For the above purposes of 
lime and flux, the stone is sold at the wharf at thirty-seven and a half cents per ton. 
Limestone lines the shore from Singsing landing to Sparta landing, where its contact with 
granite is seen. The limestone here has the aspect of having been upturned, and its layers 
pitch down towards the granite (Vide PI. 5, fig. 2). This locality is on the north side of the 
point at Sparta, on the north side of the brick-yard. The range of the above limestone is 
N. 32° E., and the ridge of granite trends in the same direction. About thirty or forty rods 
to the eastward, the dip of the limestone is sixty to seventy degrees to the eastward; but in 
a few rods to the north it is vertical, and resumes its strike of N. 20° E. 
About one hundred and fifty yards southeast of the adit that was opened to strike a vein of 
♦ I have often observed that arehitects and builders in our country rarely exercise that care in the selection of materials 
for durability, that they ought, both for their own reputation, and the profit of their employers. 
