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[Assembly 
limestones, lying unconformably upon the subjacent slate rocks. I have 
traced these rocks to within a few feet of their junction in many places. 
Over a large part of Becraft's mountain, the strata slope from 1° to 6°, 
both from the east and the west, towards the centre of the mountain, 
forming a very small segment of an inverted arch, and as the limestone 
is cavernous, and intersected by numerous fissures, most of the water 
which falls upon the mountain sinks into them and is retained. This 
peculiarity gives rise to a large limestone spring, which breaks out from 
the cliff on the north end of the mountain. It affords a constant and 
abundant supply of wholsome water for the city of Hudson. 
The lower beds of limestone of Becraft's mountain, are compact, and 
of a dark blue, or nearly black colour. It breaks with a conchoidal 
fracture, is easily dressed with a hammer, and is used for a building 
stone. It is beautiful and durable. The new Presbyterian church in 
Hudson, is built of this material. Quarries have been extensively 
wrought in these beds, on the west side of the mountain. It has also 
been used for making lime. 
The middle beds of Becraft's mountain are slaty limestones, and filled 
with fossil remains. Some layers are suitable for building, but gene- 
rally they are adapted only for common wall stone. Some of the strata 
would probably make hydraulic cement. 
The upper beds of limestone in this mountain, are distinctly cry- 
stalline, and replete with fossil remains. There are several quarries 
in these beds near the summit of the mountain. The stone is mostly em- 
ployed for rough wall stone, for basement walls, and some of it has been 
used for making lime, for which purpose it is well adapted. This stone 
receives a high polish, and makes a beautiful gray marble with a tint of 
red. I have seen chimney pieces which were made of this material that 
were very beautiful. Mr. Charles Darling, of Hudson, wrought one of 
the quarries as a marble some years ago, but the demand was not suffi- 
cient to justify its continuance. The following description is an accu- 
rate one, as might be inferred from the distinguished author of it. Prof. 
Silliman. 
" The marble is of a grayish colour, with a slight blush of red; its 
structure is semicrystalline, and in some places highly crystalline, espe- 
cially in and around the organized bodies, which in vast numbers it em- 
braces. Among them the encrinite is very conspicuous and frequent, 
and when the marble is polished, the organized bodies congealed in a 
bright calcareous bed, and often more brilliant themselves than the me- 
