352 Brace on the Minerals of Litchfield. 
begins at Mount Prospect, between Litchfield and Warren, and 
runs through South Farms, Bethlem and Watertown, The 
oryisals of feldspar in it are often very perfect. , 
_ The primitive granite, asa rock, is not found, though it lies 
scattered on the surface in great quantities, and large masses. 
The graphic granite in this region-is often remarkably fine, 
Mica slate constitutes a considerable part of those rocks that 
rest on the gneiss, though never found in such elevated situa- 
tions. ‘The mica slate rocks are always inclined at a great an- 
gle with the horizon, and follow the direction of the other 
range. Litchfield village, Chesnut hill, and a great part of Har- 
wington, are entirely composed of this rock, The Bantum and 
the Waterbury rivers have their bottoms of it. Some of the 
brooks entering the Waterbury, have cut their passages through 
the mica slate, leaving walls of 40 or 50 feet on each side, tra- 
ersed by veins of a very coarse-grained granite, and often - 
- much mixed with sulphuret of iron. The slate near Harwing- 
ton meeting-house contains a great quantity of sulphuret of 
iron. Mica slate likewise lies on the sides of the gneiss range 
in Canaan and Salisbury, where it dips under the limestone. 
Sienite is scattered on the surface in large masses, especially 
where the porphyritic gneiss is found. Some times however 
the masses are so large as to form mountains. Mount Tom, 
between Litchfield and Washington, is of this nature, being 
entirely composed of sienite, resting on gneiss. Slaty sienite 
is frequently found, having a very large proportion of horn- 
blende. : 
The minerals that are found in this region, are much more 
interesting than its geology. — In describing them I shall con- 
fine myself to the district east of the limestone range, intending 
at some future time to investigate and describe the limestone 
country. 
Carbonate of lime, the granular limestone, is scattered over 
the whole of this region, It often is found in the cavities of 
decayed quartz rocks, and contains tremolite and augite. 
Cyanue or Sappar, is found in. great quantities, especially in 
Harwington and Litchfield. A crystalline mass of this was 
found a few years ago, weighing probably 15 cwt. ; “it lay on @ 
