1914-] CONCEPTION AND TRINITY BAYS, NEWFOUNDLAND. 433 



foundland, manganese has been described by Murray and Howley 

 as a massive carbonate bed interbedded with slates of " Silurian " 

 age. Dr. T. Sterry Hunt (12: 204 and 205) described this 

 mineral as 



" compact and impalpable in texture, brittle, with a conchoidal fracture and 

 a feeble waxy luster ; slightly translucent on the thin edges ; color fawn 

 to pale chestnut-brown ; streak white, hardness 4.0 ; density 3.25. The speci- 

 men shows faint lines which seem to be those of deposition and give to the 

 mass the aspect of a sinter. It is encrusted and penetrated in parts with 

 black crystalline oxide of manganese. The presence of oxide of manganese 

 in this mineral is probably due to its partial decomposition." Analysis of this 

 mineral by Dr. Hunt is as follows : 



MnCOs 84.6 



SiO, 14.40 



Fe, CaO and MgO traces 



"This deposit is of interest on account of the existence of the metal in the 

 form of a bedded carbonate. It probably represents the former condition of 

 many of the oxide ores of manganese elsewhere in the stratified rocks, but 

 they have since been converted to their more stable form." 



It is quite evident from the above description of the Placentia 

 Bay manganese that we have in all probability a deposit similar in 

 mineralogic character and stratigraphic position to those in Concep- 

 tion Bay. No published stratigraphical or paleeontological work has 

 appeared on the Placentia Bay occurrences. In that portion of this 

 paper relating to the stratigraphy of the manganese deposits it will 

 be readily seen that the basin into which the manganiferous muds 

 were deposited to form the present manganese beds of the lower 

 Cambrian probably extended to or covered Placentia Bay or that por- 

 tion of Placentia Bay where we now find Cambrian rocks. There is 

 no doubt that the " Silurian rocks " referred to above by Howley 

 and Murray are the lower Cambrian. 



Wales. — Sedimentary manganese deposits have been described 

 as occurring in the Cambrian rocks of Merionethshire, North Wales 

 by Mr. Edward Halse (9: 156) in an article entitled, "The Occur- 

 rence of Manganese Ore in the Cambrian Rocks of Merionethshire." 

 He says : 



" in the Harlech mine, the bed of ore is a little over a foot thick, consisting 

 of grit of medium grain, overlaid by a thin band of quartzite, probably meta- 



