18 MINERAL RESOURCES OP ALABAMA. 



Considerable magnetite has been observed at a number of 

 points in the region of our metrnorphic rocks, but as yet not 

 in sufficient quantity to be commercially used. 



(4.) BLACK BAND AND CLAY IRON STONE:: The black 

 band is a highly carbonaceous variety of the carbonate ore, oc- 

 curring at a number of points in the Coal Measures. It has 

 been mined or quarried at only a few places and then only to a 

 very limited extent. Some experiments have been made with 

 it in the furnaces both in the raw and calcined state. 



The Clay iron stone occurs in regular seams and in rounded 

 and flattened concretions in the strata of the Coal Measures, 

 and also in the lower Cretaceous and in the Tertiary forma- 

 tions, in none of which, however, has it yet been demonstrated 

 to be of any commercial importance. As result of the weath- 

 ing and disintegration of this ore are found occasionally some 

 very good deposits of limonite or brown ore. 



In connection with iron ores two closely associated minerals 

 may appropriately be described, viz., manganese ores and 

 bauxite. 



Manganese Ores. 



Pyrolusite and Psilomelane occur in a number of localities 

 in Cleburne, Calhoun, Blount and Cherokee counties in quan- 

 tity sufficient to make them of probable commercial value. 



Several of these deposits in the Weisner formation in Cle- 

 burne county have been worked and have furnished probably 

 the greater part of the pure manganese ore that has been 

 mined in the state. 



Manganiferous limonite has been mined to some extent near 

 Anniston and converted into Spiegel eisen and ferro-manga- 

 nese in the Anniston furnaces. 



In its mode of occurrence manganese ore is very similar to 

 brown iron ore, with which it is closely associated, most of the 

 brown ore banks containing more or less of it, and it often 

 happens that the same deposit is partly limonite and partly 

 manganese ore. The Blount county deposits of this kind are 

 near the base of the Fort Payne chert of the Lower Carbon- 

 iferous, those of Cherokee, Tuscaloosa and other counties are 

 in the Knox Dolomite. 



