390 
DESCRIPTIVE MINERALOGY. 
Fig. 224. 
Fig. 225. 
beautiful actynolite of a pale green colour, in a white talcose rock. It is in long slender 
prisms both straight and bent, and intersected by transverse seams. 
Tremolite of a white and bluish white colour, is found in the white limestone in various 
parts of the town of Dover. It is similar to that to be hereafter described as occurring in 
Nevv-York and Westchester counties. 
Essex County. There are localities of common hornblende in various parts of this county. 
At almost all the mines of magnetic iron ore, it is one of the accompanying minerals. It is 
usually black and massive; sometimes it is white, has a high vitreous lustre, and is streaked 
in the direction of the cleavage surfaces. Such specimens often occur at the Crag-Harbour 
mine, near Port Henry. 
At Willsborough, nine miles northwest of the village of 
Essex, small but perfect black crystals are imbedded in 
black tourmaline. The forms are the triunitaire of Haiiy, 
Fig. 224 ; and the accelere of Haiiy, Fig. 225. M on s 
152° 17'; M' on x 117° 43'; l on a? 105° IP; l on l 
110° 2'; r on r 149° 38'; i on x 129° 8' (Shepard). 
Fine massive black hornblende, having a high lustre, is 
found at the Barnum iron mine, about six miles west of 
Port Henry. It forms a part of the walls of the mine. 
The same variety also occurs near the locality of garnet 
and tabular spar in the town of Lewis. 
At the Sanford ore bed, in the western part of Moriah, 
there is a variety of actynolite quite similar to that found in Orange county. And at another 
mine having the same name, six miles west of Port Henry, veins of asbestus run through the 
ore and the accompanying rock. 
Of the granular variety of hornblende, it is scarcely necessary to enumerate the localities, 
as it is found at almost all the deposits of iron ore. 
Jefferson County. In the vicinity of Watertown, there are two varieties of tremolite. 
The one is in the form of white translucent fibres, or bundles of fibres, which are variously 
bent or divergent; the other is dark brown, greyish brown and greyish white, and consists of 
bundles of flat prismatic fibres which are bent and divergent. 
The variety amianthus occurs in thin veins, associated witli serpentine, in the white lime¬ 
stone near the village of Oxbow. 
New-York County. A beautiful white and bluish white tremolite is found in the quarries 
of dolomite at Kingsbridge. In some cases it is in broad laminated masses, which have a 
semi-crystalline structure and a high vitreous lustre, and is intersected by transverse seams. 
Other specimens exhibit fasciculated groups of minute, diverging or interlacing fibres. It is 
not unusual, in this and the adjoining county, to find the tremolite passing into pyroxene ; and 
the purest specimens usually effervesce slightly with acids, in consequence of the mixture of 
dolomite. The folia of tremolite, occurring at Kingsbridge, are sometimes six to nine inches 
in length. 
