22 Bulletin of the New York State Museum. 



of phosphorus. About 30,000 tons of ore have been shipped to furnaces 

 in Pennsylvania, and there are, it is estimated, at least 100,000 tons of 

 lean ore on the dump. Concentrating works, equipped with crushers 

 and Conkling jigs were put up in 1883. During the past season ex- 

 periments in separating the magnetite and the rock by a magnetic 

 separator have been carried on, and it has been decided to set up a 

 plant to concentrate the ore in this way. So far the results prove 

 that the average of the dump containing thirty-eight per cent of iron, 

 can be concentrated to sixty-two per cent. The Ramel Carbu- 

 retted Iron Company has built a small mill near the mine and reduced 

 the fine concentrated ore in Conley patent retorts. Their product is 

 sold to open hearth steel furnaces. These mines are the property of 

 the Croton Magnetic Iron Mines Company, J. D. Cheever, treas- 

 urer, 51 Park Row, New York. A wire tramway connects the 

 mines with the New York and Harlem R. R. line about two miles 

 south-west of Brewster. 



This range of ore was described by Prof. Mather as one of great 

 extent, in his report on the First Geological District of the State.* 



BREWSTER MINE, Southeast, Putnam County.— The mine 

 in the village of Brewster has not been in operation since 1880. Its. 

 workings run under the New York and Harlem railroad. The 

 " shoots " of ore were small and irregular in form, and are said to 

 be exhausted. 



TILLY FOSTER MINE, Southeast, Putnam County. — This 

 large and well-known mine is on the line of the New. York and 

 Northern railroad, two miles north-west of Brewster. The extensive 

 mining operations here have proven the existence of a large body of 

 valuable ore, and brought to light some notable facts in the geologi- 

 cal structure of the ore body, indicative of great changes in its shape 

 and position, and affording excellent illustrations of the way in which 

 these Archaean rocks have been uplifted and disturbed. The strike 

 of the enclosing gneissic strata is, in general, a few degrees north of 

 north-east, and the dip is at a high angle (70°) to the east-south- 

 east. The ore has been exploited for a length of 1,500 feet, and a 

 depth of 630 feet, in the deepest (middle or Cheever slope). The 

 breadth of ore is 160 feet in the middle, narrowing to 80 feet 

 towards either end. This great breadth of ore is explained by a 



* Geology of the First Geological District, by Wm. W. Mather, Albany, 1843, pp. 

 560-561. 



