Kemp — Geology of Essex County. 



613 



merits are of course based on the supposition that titaniferous ores are 

 mechanical mixtures of normal magnetite with ilmenite, but there is little 

 reason to doubt that where the percentage of Ti0 2 is considerable, say ten 

 and above, the mixture is either so intimate as not to be economically broken 

 up, or else it is actually a chemical combination in the nature of ilmenite or 

 some related mineral. Mere magnetism does not preclude titanium, for O. A. 

 Derby has found in Brazil, natural lode-stone with twenty per cent. Ti0 2 . 



Indications of ore have been met across the divide to the east of the 

 Sanford ore-bed and in the watershed of the Opalescent river. I have not 

 visited the locality, as but little work has been expended on it and none in 

 fact since the early operations. 



About a mile west of lake Sanford is the Cheney ore-bed that presents 

 some differences both in composition and in wall rock from others. Professor 

 Emmons, on Plate III of his report, calls the wall rock " sienitic," but it 

 really is a gneissoid variety of gabbro, having a laminated structure visibly 

 developed, while the minerals are those of the familiar gabbros of the 

 region. Dark silicates are much more abundant than in the anorthosites that 

 form the walls of the other veins. I did not personally visit the Cheney 

 exposure, but specimens of the ore and wall rock were obtained by Mr. James 

 MacNaughton and kindly furnished to me. I understand that forty or fifty 

 feet of ore are exposed without showing the walls. The following analyses 

 illustrate the composition. They were published by Mr. Rossi in the 

 Iron Age, February 6, 1896. 





Wilbur. 



Rossi. 





(Rich Oee.) 



(Poor Ore.) 



Si0 2 





9.79 



TiO, 



8.25 



15.77 



ALA 





7.12 



CuO 





8.89 



MgO 





3.00 



Mn 3 4 . . 







Fe 3 4 



86.53 



55.64 



P • 



0.39 





S 



0.74 



1.00 



Fe 



62.15 



40.33 



