1914-1 CONCEPTION AND TRINITY BAYS, .NEWFOUNDLAND. 401 



Of most interest in connection with this red shaly band are the 

 jaspery bands of green and brown carbonate and oxide of manga- 

 nese. Where in bands, they vary from }i inch to i inch -{- in thick- 

 ness and may be continuous. The contact with the red band may 

 be very even or very undulatory. This wavy character may be 

 present whether the band thickens or thins or is of the same thick- 

 ness throughout. The brown and green jaspery bands may contain 

 thin laminse or nodules of other colors. 



The green material is characterized by its chalcedonic and some- 

 what waxy luster^ its translucency on thin edges, its hardness of 5 to 

 6, its specific gravity of about 3.13 (that of the green nodule) and 

 its slight response to HCl. 



The chemical analysis of this material is as follows : 



Analysis A. Analysis A i. 



Green Band. Recalculation. 



SiO. 7-24 MnCO,, 44.39 



FeA 3-36 MnO^ 8.08 



FeO 3.21 CaCO,, 20.11 



ALO3 6.11 MgCO, 4-21 



MnO 35-53 FeO 3-36 



CaO 11.30 H,0 86 



MgO 2.30 2H,0-AL03-2SiO,-fFeO .... 18.24 



H.O 2.98 



COo 28.06 



100.09 



99-25 



The green band so very similar chemically to the green nodule 

 already described in connection with the nodular bed lower down in 

 the series, is in great part a rhodochrosite in composition but has 

 in combination, in descending order of abundance, considerable 

 amounts of calcareous, argillaceous and ferruginous material. Man- 

 ganese not combined with COo probably exists as some oxide, prob- 

 ably a peroxide, as considerable chlorine was given ofif by the sample 

 when first treated with concentrated HCl. Other features hardly 

 need any explanation. 



Thin sections of this band are very unsatisfactory in that, be- 

 cause of the impalpable fineness of the grain, little can be seen out- 

 side of structural features and certain opaque minerals, chiefly 

 hematite. 



