416 



DALE— CAMBRIAN MANGANESE DEPOSITS OF [April 25, 



ing carbonate centers, are found most frequently in the jaspery 

 bands. The spherules vary in size from 12 to 120 microns but 

 have average diameter of about 94 microns. 



The chemical analysis of this bed, with its recalculation, is as 

 follows : 



2ig E 6. 



SiO, 18.24 



FeoOa 10.01 



AloOs 1452 



MnO 10.42 



CaO 13.74 



MgO 4-94 



P,0, 1.71 



COo 24.01 



H3O 2.07 



99.66 



Recalculation. 



MnCOa 16.79 



CaCOo 20.91 



MgCOa 10.57 



FeCOa 4-52 



Fe.Os 5-49 



Ca^CPO,), 3.75 



SiOo 1.20 



2H,0AL0,-2Si0, 36.38 



99.61 



From the above analysis, this rock is essentially a dolomitic 

 manganiferous ferruginous shale with considerable amounts of 

 C2..{'FOi)n. Among the microscopically observable minerals in the 

 above recalculation are calcite, hematite, quartz. The nodular por- 

 tions, usually isotropic and of exceedingly fine grain, are probably 



Fig. 35. Photograph of manganese prospect along the KelHgrews high- 

 way just south of Long Pond; Loc. 219 F. 



