I9I4.] CONCEPTION AND TRINITY BAYS, NEWFOUNDLAND. 421 



The groundmass consists of chlorite and, for the most part, of an 

 indeterminable material. Calcite occurs as an alteration product 

 or as a constituent of the hematitic spherules. Quartz is found 

 composing infrequent aggregates and as vein-filling material. The 

 opaque minerals other than hematite are manganese as psilomelane 

 or some other secondary derivative, pyrite as disseminations, and 



\i 



vR. t ^> 



"X 







Fig. 38. Photograph of manganese prospect on Brigus South Head; Loc. 

 212 Ai2a. a, oxidized manganese beds ; b, green shale. 



limonite as a yellow staining. The spherules are for the most part 

 hematite in composition but carbonate is a very common constituent. 

 The diameters of the spherules range from 21 to 159 microns but 

 average around 44 and yy microns. The ferruginous centers of 

 some of the spherules measure 0.8 of a micron. 



Certain discoidal nodules in 213 L 4c resemble those of 219 A 4 

 at Manuels though they are very much less abundant. 



213 L 4a is nodular and the texture exceedingly fine-grained and 

 locally crystalline. The greater portion of the thin section is prob- 

 ably composed of shale material and the remainder is taken up in 

 great part by calcite and carbonate disseminations, as replacement 

 material of hyolithes shells, or as mineral aggregates. Barite occurs 



