470 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.68. 



The low hill on which the tungsten mine is located consists of a 

 flat lying bed of crystalline limestone, approximately 40 feet in 

 thickness, between beds of hornblende schist. The scheelite and 

 wolframite are reported to have occurred in a quartz layer at the 

 lower contact of the limestone, and to have represented a contact 

 metamorphic deposit. Hobbs regards the hornblende schist as be- 

 ing an altered diorite, but Hess^ states that it may bo altered 

 volcanic tuff. It bears considerable resemblance to the amphibolite 

 of Chester, Massachusetts. The limestone is thinly laminated white 

 crystalline marble, containing bedded lines of metamorphic min- 

 erals throughout. These are the characteristic minerals of region- 

 ally metamorphosed limestones throughout the Taconic region 

 ratlier than minerals of true contact origin. Recognizable contact 

 metamorphism traceable to visible igneous masses is absent. The 

 main opening of the mine is at the site of the burned mill near the 

 railroad. This is a large quarry, exposing the whole width of the 

 limestone bed. The lower contact of this bed is covered by water 

 in the bottom of this pit, but is well exposed at the north end 

 of the opening. The lowest bed of the limestone is here much 

 stained by limonite, and is somewhat porous from leaching. Nar- 

 row quartz veins up to a foot in width penetrate this bed from 

 below, and break up and die out soon after entering the limestone. 

 This lowest rust stained limestone bed contains much marcasite in 

 disseminated form and as veins up to 2 inches in width. The quartz 

 veins contain mica of the margarodite variety, topaz, and a very 

 black sphalerite. No scheelite or wolframite was found, although 

 these minerals might be expected in this association. In the bot- 

 tom of the main pit a dike of ordinary granite pegmatite rich in 

 feldspar and biotite is exposed. An old tramway leads up around 

 the north side of the hill for a thousand feet to the " Upper Mine," 

 also located at the base of the limestone bed. Here little can be 

 learned as to the geologic structure or the nature or occurrence of 

 the ore, as the pit is filled with water. The walls are crumpled and 

 cut by small faults, and the rock is much weathered and stained with 

 limonite. Below the tramway, midway between the lower and upper 

 openings, is the " Champion lode." This is a vein, apparently con- 

 sisting of pure vitreous quartz which was mined for wood filler. 

 The vein which was from 4 to 6 feet wide has perfectly smooth and 

 almost vertical walls. About 800 feet due south of the upper mine 

 opening is a small pit, from which marble has been quarried and 

 burned to quicklime. The marble, like that of the main pit, is 

 thin bedded and rather impure from the presence of metamorpliic 

 silicates. Some of it is distinctly pink, while other portions are 



1 Iless, Frank L., Tungsten minerals and deposits. Bull. U. S. Geol. Survev No. CSQ. 

 p. 41. 1917. 



