436 
GEOLOGY OF THE FIRST DISTRICT. 
The limestone about Pineplains seems to divide into two branches, one of which ranges 
by the south end of Mount Stessing (where it is underlaid by the Potsdam sandstone resting 
on gneiss), down Wappinger’s creek to Barnegate, which has been described as the Barne- 
gate limestone ; the other up the valley of the Chicomeco creek, through the western part of 
Northeast, the western part of Amenia, the eastern part of Washington by Lithgow and Mab- 
bitsville, and down the clove through Unionvale and Beekman into Fishkill. Another branch 
of this limestoiie ranges from Stamford through Washington to half a mile east of Verbank 
in Unionvale, to Poughquaick in Beekman, and thence down the Fishkill creek to Matteawan. 
In many places near the mica slate and gneiss of the Chesnut ridge (which is the southern 
extension of Winchell’s mountain south towards the Highlands), and especially in the low 
valleys, the limestone is altered to a grey and white granular limestone more or less dolomitic, 
like that of the Dover and Oblong valley east of Chesnut ridge and Winchell’s mountain, 
and like that of Berkshire county in Massachusetts, and the southwest part of Vermont. 
Continuation of details of the Taconic rocks. About a quarter of a mile southeast of Pulver’s 
corners in Pineplains, on the east side of WinchelFs mountain, the junction of the slate and 
sparry limestone was observed. Both dipped slightly to the west, the slate being on the west 
side. 
A quarry of talcy argillaceous slate, containing cubic cavities in which crystals of pyrites 
have been embedded, was seen on the east side of Winchell’s mountain, about a quarter of a 
mile north of Pulver’s corners. The rock is similar to that of Foster’s slate quarries, in the 
west part of Hillsdale. The rock of this quarry is used for the lining of furnaces, and when 
laid with the edges to the inside of the stack, resists the heat almost as well as fire bricks. 
The Ancram or Livingston lead mine is in the talco-argillaceous slate, a few rods from its 
junction with the sparry limestone, both rocks dipping to the south-southeast at a high angle 
(Vide PI. 23, fig. 4). 
The numerous excavations for lead and copper in southeast, were made in 1740, and during 
the Revolution, on the farms of Mr. Abraham Bockee and Mr. Ward Bryan. They are in 
the limestone, which is grey and subgranular. The talco-argillaceous slate is within a few 
rods to the west, and both dip at a high angle to the eastward (Vide PI. 23, fig. 5). 
Prof. Merrick observed a slaty and talcy limestone at the base of a hill a little west of the 
village of Separate, very similar to the rock at Lebanon springs. Talco-micaceous slate lies 
next on the east, and talco-argillaceous slate on the west, traversed by veins of quartz. The 
fragments of quartz are very much scattered over the surface. The talco-argillaceous slate 
becomes less talcy on the west, and forms the range of hills in the east part of Stanford, and 
the rock is very much contorted. 
A few rods west of Thompson’s pond, he observed limestone that he thinks would make a 
fine clouded marble, but only a small area of the rock was exposed. 
The granular quartz rock at the southwest end of Mount Stessing in Pineplains and Stan¬ 
ford, already described as the Potsdam sandstone, may, from its modified character, be con¬ 
sidered as belonging to the Taconic rocks. It is nearly horizontal in position, reposing on 
