MURPHREE'S VALLEY.; ECONOMIC GEOLOGY. 93 



makes the base of the Trenton. At a few places along this 

 line, limonite ore has been found ; and in at least one place 

 in S. 20, T. 13, R. 1, E., in such quantities as to leave no 

 doubt of its being a belt or horizon of limonite ore. The 

 ore bed here, though not very extensive, is peculiar in car- 

 rying a mixture of limonite and turgite combined. Also in 

 S. 28, T. 14, R. 1, W.. near Village Springs, good limonite 

 was found, which could only be referred to this horizon. 



The Fifth Limonite Horizon is more important. It is the 

 upper part of the Siliceous Group of the Sub Carboniferous. 

 The belt carrying ore does not seem to be continuous here, 

 but in a few places it carries large amounts of good brown 

 ore. One of these places is in S. 16, T. 12, R. 2, E. Ore of 

 very fine quality exists here, and in quantity sufficient to 

 establish this as a brown ore bearing horizon. It was seen 

 at many places along Sand valley, at or near the base of the 

 LaGrange Sandstone ; but the most prominent deposit of it 

 occurs on the S. E. side of the valley in S. 5, T. 13, R. 2, E. 

 It exists here in great volume between the Sub-Carboniferous 

 Chert and the LaGrange Sandstone. Some of it is very 

 cherty and impure, but much of it, especially the lower por- 

 tion of the ledge, is excellent ore. Its surroundings here 

 clearly show that this is Sub-Carboniferous ore, though, by 

 faulting, it is thrown in close proximity to the Silurian ore 

 of horizon No. 1. It is also seen at the base of the iron 

 ridge in-S. 33, T. 12, R. 2, E., associated with the same Sub- 

 Carboniferous rocks, and showing the same characteristics. 



The Sixth Limonite. Horizon is the top of Carboniferous or 

 Mountain Limestone, or the base of the Sub-Conglomerate 

 Coal Measures. 



Almost continuously along this line is found a belt of 

 brown ore, though seldom in quantity sufficient to be of 

 practicable value. 



The iron ore in this horizon is often good limonite, but 

 generally sandy ; and in many places replaced by carbonate 

 or spathic ore, some places in considerable volume. This 



