I9I4.] CONCEPTION AND TRINITY BAYS, NEWFOUNDLAND. 413 



Analysis /. Analysis / i. 



2ig E 4 Recalculation. 



SiO. 18.04 MnO, 34.25 



Fe.Os 4.82 MnCOs 1 1.27 



ALO3 6.58 CaCO., 400 



MnO 41.26 MgCOa 4.97 



CaO 2.24 SiO^ 10.32 



MgO 2.39 BaSO.4 5.40 



BaSOi 540 Fe.Os 4.82 



CO, 8.34 2H,0-AL0,v2Si0, 16.30 



H,6 7.98 H,0 5.41 



97-05 96.74 



This is essentially a hydrous oxide of manganese with consider- 

 able amounts of argillaceous material, rhodochrosite, silicious 

 matter, dolomite, barite and hematite in descending order of 

 abundance. 



219 E 6, not a manganese ore bed, though manganiferous, is 

 of interest mineralogically and petrographically. In structure it is 

 concretionary and banded, nodular and microscopically oolitic. It 

 is essentially a calcareous, ferruginous and manganiferous nodular 

 and banded shale (see Fig. 32). Under the microscope the greater 

 part of the groundmass, isotropic under crossed nicols, is of inde- 

 terminable composition simulating phosphatic material. Of the 

 anisotropic minerals, calcite is most frequent and occurs with other 

 carbonate material in bands which show an oolitic structure. The 

 individual spherules, subspherical to elliptical in form show either 

 concentric or radiated structure, the latter showing an interference 

 cross with crossed nicols (Fig. 33, Slide 272). Calcite frequently 

 has the curved twinning planes indicative of strain. Barite occurs 

 in narrow veins or bands, as disseminated blades, or as sheath-like 

 blades or aggregations, usually being replaced to a greater or less 

 extent by chlorite and in a few instances by pyrite (Fig. 34, Slide 

 272). The spherules consist of hematitic pigment, carbonate and 

 chlorite. Because of the frequent association of chlorite with barite 

 one is led to suspect that possibly the chlorite spherules were 

 originally of barite which has since been replaced by the chlorite. 

 Other spherules made up in great part of hematite, sometimes show- 



