1914.] CONCEPTION AND TRINITY BAYS, NEWFOUNDLAND. 403 



foot in thickness. Green discoidal nodules of manganese carbonate 

 and the green, brown and red manganiferous bands similar to those 

 of 219 A 4 are a conspicuous feature of the bed. A thin section 

 from one of the nodules of this bed collected during the summer of 

 1912 shows, aside from the nodular form, conspicuous zonal and 



«' imJT ■.■utittia.i ■l^^hr'^BrML wi^^dtlLimmJIf^ 



Fig. 24. Microphotograph of red shale from 219 AS; slide 284; enlarged 

 38 diam. a, hematite aggregation ; b, spherules of hematite. 



oolitic structures. For the most part the grain is impalpable, but 

 that of the core is more or less crystalline. There are five pro- 

 nounced parts consisting of a crystalline innermost core. No. i, 

 which in a great part is composed of carbonate, presumably that of 

 calcium and manganese though nothing of a definite confirmatory 

 nature could be observed, and 4 successive enveloping shells differ- 

 entiated from each other by either the presence or absence of hema- 

 tite, the shade or intensity of color or by fineness of grain. The 

 oolitic character of zones 3 and 5 with spherules consisting in great 

 part of hematite and measuring as small as 12 microns and as large 

 as 90 is very noticeable. Layers 2 and 4 in a great degree consist of 



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