IRON ORES OF NEW YORK 537 



Millpond is the largest, with about 12 feet of solid ore, that was 

 mined to a considerable extent in the early days. It really 

 appears to be one streak in a large belt. Analyses have yielded 

 over 60 per cent. iron. 



There are several important belts of attraction in addition to 

 this and other outcrops that have not been much, if at all, opened 

 up. One has been also found on the west shore of Lake Hender- 

 son, and float has been noted off to the northwest near the 

 Preston ponds. In addition to these, a number of belts have 

 been shown by the dipping needle back in the hills and also 

 further south near the lower works, now called Tahawus. 



Several experimental runs have been made with these ores to 

 test whether the generally prevalent prejudice against titanifer- 

 ous magnetite was well based or not. The results of the first 

 series have been set forth by Mr. August Rossi in the Trans- 

 Amer. Institute Mining Engineers, vol. xxi (pp. 832-867), 1893. 

 The past spring a more extended run in a small blast furnace of 

 about 20 feet in height was made at Buffalo on 15<> tons of ore. 

 By calculating the slag on the composition of titanite or sphene, 

 or, rather, some of its allied minerals, and allowing Ti0 2 to 

 replace Si0 2 up to 42 per cent., no difficulty was experienced and 

 an iron of very superior properties for car wheels and chilled 

 castings was produced. Mr. Rossi, who conducted the run, is 

 intending to describe it at length at an early date. 



III. Hematite Ores of St. Lawrence and Jefferson Counties. 



The hematites, or red hematites, as distinguished from the 

 brown hematites (limonites) are mined in a narrow belt, scarcely 

 30 miles long, stretching from Philadelphia, in Jefferson 

 county, northeast into Hermon, in St. Lawrence county. The 

 ore deposits are found associated with a so-called serpentine rock, 

 and lying between the Potsdam sandstone and the crystalline 

 rocks of the Archaean age. The geological horizon appears to be 

 below the Potsdam, and it is probably Huronian, although it has 

 not been so recognized by Dr. T. S. Hunt in his references to* 

 the hematites of Canada and northern New York. The deposits 

 are found to be very irregular in shape, due apparently to the 



* '• On the Mineralogy of the Laurentian Limestones of North America," in the 21st Ann. 

 R^pjrt of the Regents of the University of New Yjrk, Albany, 1871, pp. 88-89. 



