ON THE GENETIC SIGNIFICANCE OF FERROUS SILICATE 

 ASSOCIATED WITH THE CLINTON IRON ORES 



BY C. H. SMYTH, JR 



In earlier papers dealing with the Clinton iron ores, the writer 1 has 

 called attention to the occurrence of small quantities of gray and 

 green oolites, intimately associated with the ores but more or less 

 clearly characterized by their peculiar colors. 



The paper last cited refers briefly to the possible bearing of these 

 oolites upon the problem of the genesis of the ores and, in this con- 

 nection, mention is made of similar occurrences in association with 

 other ores that seem to be of the same general type. 



The present paper is a further discussion of this phase of the ore 

 problem and is therefore largely confined to certain features shown 

 chiefly by the gray and green oolites and to a less extent only by the 

 ordinary ores. 



In this connection, particular interest attaches to a dark gray, 

 nearly black, oolite which is well shown at the upper end of a ravine 

 on the Burns farm, about one-half of a mile east of the Borst mines 

 (the only mines now in operation) at Clinton, N. Y., at a point 

 where a small stream flows through some abandoned surface work- 

 ings. The ore has been removed but the underlying shales and 

 thin sandstones show in a section about 15 feet in thickness. The 

 gray oolite forms a bed 1 to 2 inches thick, lying about a foot below 

 the ore horizon and separated from it by a dense, tough, arenaceous 

 shale. The oolite layer is made up of nearly, or quite, discontin- 

 uous lenses, the upper surface being marked by convexities measured, 

 vertically, by the thickness of the bed and, horizontally, by a foot 

 or thereabouts, while the lower surface is approximately plane. 

 The shales above and below the oolite cling tenaciously to it when 

 specimens are broken out. 



The general appearance of the oolite would be that of a low- 

 grade Clinton oolitic ore, were it not for the difference in color, the 

 spherules being dark gray to black, instead of red, and dominating 

 the color of the rock as a whole. There is, however, a subsidiary 



1 On the Clinton Iron Ore: Am. Jour. Sci. (3) 43, p. 487-96, 1892. 



Die Hamatite von Clinton in den ostlichen Vereinigten Staaten: Zeits. prakt. 

 Geol., Jahrgang 1894, p. 304-13, 1894. 



The Clinton Type of Iron Ore Deposits: Types of Ore Deposits. H. F. Bain 

 et al. p. 33-5i> 19"- 



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