252 



ECONOMIC GEOLOGY 



ment deposits, and as veins and breccia cement in a fault fissure 

 in jasper. 



FIG.~ 125. The manganese deposits at Pedras Pretas, near Bahia, Brazil, 

 as shown by shafts and pits. 



In Cuba, near Santiago, pyrolusite, manganite, braunite and 

 wad occur as replacement deposits with jaspers. Perhaps the 

 Brazilian deposits are the most noted ore bodies of manganese in 



E 



48km- 



FIG. .126. Section across the Cretaceous basin of Bahia, Brazil, showing 

 the geologic position of manganese deposits. 



the world. (See Figs. 125 and 126) . The ore is from 25 to 30 ft. 

 in thickness and thins out toward the edges producing large lens- 



