I9I4-] CONCEPTION AND TRINITY BAYS, NEWFOUNDLAND. 445 



supposed that manganese exists in solution as a bicarbonate or a 

 sulphate. In their work on the Blue Muds of the Clyde Sea area, 

 Murray and Irvine (19: 728) found that the bicarbonate of man- 

 ganese was derived "first from the direct decomposition of the 

 rock fragments in the mud by the alkaline carbonates in the sea 

 water or, second, from the reduction of the higher oxides of man- 

 ganese by the organic matter in the muds." In many respects the 

 Clyde Sea area of England is similar to what the lower Cambrian 

 sea of Newfoundland must have been. It receives detritus and 

 waters draining lands which are in large part of an igneous and 

 sedimentary character (19: 780). 



" What is known as the Clyde Sea Area consists of a series of sub- 

 marine basins, separated from each other by submarine barriers. The depth 

 of the basins ranges from 30 to 106 fathoms, and the depth of water over 

 the intervening ridges varies from 3 to 15 fathoms. In all the deeper parts 

 of the basins there is a bluish mud, in which, as a rule, no manganese nodules 

 are found, but on the immediate surface of the deposit of Blue Mud there 

 is a surface layer with a reddish or light gray color, in which deposits of 

 manganese dioxide occur. When stones are dredged from these muds many 

 of them are surrounded by a dark ring of manganese dioxide, marking the 

 depth to which they have been embedded in the mud. The whole upper sur- 

 face of the stones has likewise a slight coating of manganese, while a portion 

 imbedded in the mud is free from these manganese deposits." 



He goes on to say that 



"The formation of manganese nodules on the immediate surface of the 

 deposit, on the tops of the barriers, and in the pit-like depressions, is most 

 probably to be accounted for by the more abundant supply of oxygen, or the 

 diminished amount of decomposing organic matter in these positions." 



A somewhat similar set of conditions probably was present in the 

 muds and superjacent sea water of the Cambrian basin of New- 

 foundland with the exception that instead of all the bicarbonate 

 being converted into the dioxide the greater proportion of it was 

 precipitated as the carbonate of manganese (MnCO,). The libera- 

 tion of CO2 from the bicarbonate of calcium in solution has been 

 experimentally effected by evaporation, increasing the temperature, 

 or through agitation of the solution. It would seem to the writer 

 that the liberation of the CO2 from the manganese, calcium and 

 magnesium bicarbonates might have taken place through evapora- 



