68 JOHN BIRKINBINE 



fact, the exploited brown hematite deposits of this region are 

 of greater average extent than those found in other portions of 

 the country. Occasional deposits of magnetite are also 

 found in the Alabama-Tennessee district, but few have been 

 worked. Some carbonate ore has also been won and used in 

 the manufacture of special irons. 



Magnetite iron ores are produced chiefly in New York, 

 New Jersey, and Pennsylvania, but some are won from North 

 Carolina, Michigan, New Mexico, and Utah. The deposits of 

 this class of mineral in New York state are phenomenally 

 large, and so far as metallic contents are concerned, unusually 

 rich; but many carry phosphorus, sulphur, or titanium in 

 excess, some of the most extensive deposits having so much 

 titanium that they have not been brought into commercial 

 use. High phosphorus ores, however, have been and are 

 mined to a large extent, and beneficiated by magnetic con- 

 centration. Some ores in the vicinity of Port Henry, N. Y., 

 carry as high as 3 per cent of phosphorus, as apatite, mixed 

 with the magnetic crystals, which, after the ore is comminuted, 

 can be readily separated, either by magnetic separators or by 

 jigs. Other ores of the Port Henry mines district are of Besse- 

 mer grade, and from one opening 30,000 tons of very high 

 grade magnetic ore were obtained. This ore approached 

 chemical purity, was of Bessemer grade as to phosphorus con- 

 tents, and was practically a mass of well defined octahedral 

 crystalline forms, some an inch and a quarter on the face, 

 many having practically perfect proportions. Still larger 

 sized crystals have been found, but these were more or less 

 imperfect, and masses of crystals affected by pressure had 

 some faces flattened. 



The localities which have been worked in the Lake Cham- 

 plain district are the mines at Chateaugay, west of Plattsburg; 

 the mines at Moriah, west of Port Henry; and those west of 

 Crown Point. These deposits are at elevations of from 600 

 to 1,000 feet above the level of Lake Champlain, and while 

 some explorations originally developed beds of considerable 

 size by an open cut, most of the mining is now underground, 

 and much of it at a depth of 500 feet or more. Some mines 

 which have been exploited are adjacent to the shore of the 



