242 



GEOLOGY OF THE SECOND DISTRICT. 



tions of all the veins are composed of nearly pure ore, lying longitudinally, of the width of 

 several inches ; and betvifeen these pure lines are lines of grey and white quartz, lying also 

 parallel to the lines of ore. Sometimes portions of the veins are two-thirds quartz, and there 

 are even wider stripes of quartz without any ore at all. I refer for illustration to fig. 66, where 

 d, d, arc parallel masses of rock, quartz or some other earthy substance ; while a, is the 

 unmi.xed ore. The narrow lines of rock usually continue as deep as the mine is worked ; 

 but the wider parts, which project from the walls or sides of the vein, disappear in the pro- 

 gress of mining. 



CO. 



To prepare the ore from veins of this description, it is necessary to pulverize the whole, and 

 wash the lighter materials away by running water, or separate the iron by the magnetic sepa- 

 rating machine. 



Very few minerals are mingled with these ores, but some hornblende and feldspar appear 

 occasionally. I did not observe, at either of the openings, any sulphuret of iron, or phosphate 

 of lime or labradorite, substances common at some of the beds of which I have already 

 spoken. 



A new vein, or a new opening in one of the same veins, has been made by Col. Everest, 

 which bids fair to furnish an ore still better than any I have yet described. It is upon lot No. 

 75, Ore-bed tract, and is from three to four feet wide. It is situated some distance east of 

 the preceding, and may be traced fifty rods upon the surface. It is strongly disposed to absorb 

 oxygen, and is very obedient to the magnet, almost the whole of a given sample being taken 

 up by it : it is nearly a pure mass of oxide of iron. In the large way, it is found that two tons 

 of the ore produce one ton of iron. It does not require washing. Its dip and other geolo- 

 gical relations are similar to those of the veins already described in this section ; and in the 

 purity of its ore, it approaches more nearly to the celebrated Arnold vein in Clinton county, 

 than either of the preceding. It has not been analyzed ; and hence it is impossible to deter- 

 mine how much oxygen has been absorbed, or what are the chemical conditions of the ore. 

 It is principally to this fact that chemists should direct their attention in the analysis of ores 

 wliich work well, and which contain no injurious substance. 



