620 CENTRAL MINERAL REGION OF TEXAS. 



THE PONTOTOC BAND. 



The hard ore band drawn upon the Economic Map as passing very near 

 Pontotoc is not as well exposed as the parallel band upon the east, and it is 

 not as certain that it represents a distinct structural line. Magnetite is not 

 well displayed along its course, and the surface ores are largely segregations 

 in the later rocks. But the existence of a band of high grade ore in this 

 path is a fact, and all the evidence points to the occurrence of a source of 

 supply beneath it which is of the same character as that of the other magnet- 

 ite bands discussed in these pages. Probably the same is also true of the 

 bands of manganiferous iron ores and manganese ores which lie in the equiv- 

 alent trend farther west. This view is based upon the close relations in dis- 

 tribution which invariably exist between all classes of tiie iron ores in our 

 districts, as will be shown in treating of the derived and associated ores 

 beyond. 



THE MANGANESE AND MANGANIFEROUS IRON BANDS. 



The manganese tract defined upon the map, and already described as vari- 

 able in its outcrops, has isolated exposures of ores in the Fernandian areas 

 which may occasionally be classed more appropriately among the hard iron 

 ores. The magnetites are, however, rarely represented in the region, as far 

 as my observations go. The band farther west appears to be the most fer- 

 ruginous, 



B. THE HEMATITES. 



In the Report for 1889, the ores being classified in a somewhat different 

 manner, all the hematites were grouped together, minor divisions being based 

 upon modes of occurrence. In this place, by the present method, we have 

 to consider only those which belong to the class of belt ores. There are 

 none of much importance, however, which pursue independent courses, their 

 distribution being mostly coincident with the magnetites. In many portions 

 of the magnetite bands already described these hematites lie in associated 

 layers, but often the latter are wanting or nearly so. I do not know of any 

 instance m which any considerable layer of hematite occurs without its ac- 

 companying magnetite, except in situations entirely different from the belt 

 type of ore bodies. The analyses of hematites (Nos. 10 to 24, Table III), 

 show well their relationship to the magnetites. It will be noticed that ten of 

 them have enough of the latter mineral to give considerable percentages of 

 ferrous oxide. 



There is, it is true, a special manifestation or mode of occurrence of spec- 

 ular hematite ore in quartz. This seems to be connected with the titanifer- 



