Minerals in Talcose Slate. 



359 



Island. Its predominant direction is nearly S. E. and N. W., and its 

 dip upon an average, only about 10° to 15° N. E. Indeed, in many 

 places it is nearly horizontal. The talco-chloritic slate in the east 

 part of Smithfield and Cumberland, runs generally about 15° or 20° 

 west of south and east of north, and its dip is 20° to 30° southeast. 



The bed of steatite in Groton dips to the southeast at an angle of 

 about 30.° 



Mineral Contents. 



This rock in the Hoosac mountain range, must be regarded as a 

 metalliferous deposit. Perhaps the most important metal which it 

 contains is iron. This is found principally in two places, viz. in 

 Somerset Vt. and in Hawley, Mass. Smaller masses have been no- 

 ticed in other places ; but not in sufficient quantity to be of interest in 

 an economical point of view. At all these localities, the ore is found 

 in distinct beds in the strata; and sometimes it has a slaty structure, 

 having every appearance of a contemporaneous origin with the rock. 



I have already remarked, in the first part of my Report, that the 

 iron ore in Hawley embraces two species ; the magnetic oxide, and 

 the micaceous oxide. Both of them are of fine quality. The mica- 

 ceous oxide, especially, is as beautiful as any which has been found on 

 the globe, as the specimens will show. (No. 844.) This bed does not oc- 

 cur, as is usually stated, at the junction of the talcose and mica slate; but 

 two or three miles within the talccose slate — that is, reckoning from 

 its eastern margin. 



The most valuable ore at Somerset is the magnetic oxide. With 

 this, however, is associated, often in the same bed, the hydrate of iron. 

 Several of these beds occur in the vicinity, and sometimes they are 

 connected with dolomite. The magnetic oxide is generally granular, 

 and often easily crumbled into powder, which possesses so much bril- 

 liancy that it has been used as a substitute for smalt. It is so highly 

 magnetic that it strongly attracts the fragments of the ore that have 

 been broken off, and exhibits decided polarity ; so as to form very 

 fine specimens of the natural magnet. (No. 845.) 



The largest mass of iron ore in the region that I have undertaken 

 to describe, occurs in Cumberland, Rhode Island. It is chiefly the 

 magnetic oxide, and lies two miles northeast of the center of this 

 place. But no rock is visible for a considerable distance around this 

 large hill of iron. Sienitic granite occurs, however, not far remote in 

 one or two directions, and so does talco-chloritic slate. And upon the 



