444 DALE— CAMBRIAN MANGANESE DEPOSITS OF [April 25, 



According- to Leigh Fermor (8: 403) the origin of the deep-sea 

 nodules is summed up as follows : 



" I. The manganese, although probably partly derived from cosmic dust 

 and volcanic debris, has been mostly precipitated from solution in the sea 

 water, the manganese salts having been originally brought into the sea by 

 rivers. 



" 2. The manganese oxide, although possibly partly precipitated as a re- 

 sult of the action of the vital processes of organisms, both vegetable and 

 animal, has been mainly precipitated by calcium carbonate aided by the obscure 

 process of segregation from solution round a nucleus. 



" 3. Where the sea-bottom consists largely of calcareous sediments, the 

 precipitation may have been mainly brought about by the solution of some 

 of this calcium carbonate with the deposition of an equivalent amount of 

 manganese oxide owing to. the presence of free oxygen. 



"4. Where the sea-bottom consists of red clay, it does so because the 

 depths are there so great that the tests of thin-shelled organisms are com- 

 pletely dissolved by the sea-water before they reach the bottom. The cal- 

 careous matter in being dissolved deposits an equivalent amount of manga- 

 nese oxide, which descends to the bottom, and there acts as a nucleus for 

 the segregative extraction of manganese from the waters at the sea-bottom. 

 The deposition of manganese oxide by means of calcium carbonate associated 

 with the red clays probably also occurs to a subordinate extent, for the 

 shells of thick-shelled organisms may reach the bottom before being entirely 

 dissolved." 



This summary of Fermor's is quoted in full here because of the 

 marked divergence of his views from those of Murray and Irvine, 

 and because of the greater stress laid upon Penrose's idea of the 

 precipitation of manganese oxide by calcium carbonate. 



It is the belief of the writer that the early Cambrian Sea of south- 

 eastern Newfoundland must have had so restricted and shallow a 

 character as to allow of a concentration of the manganese salts 

 sufficient to form deposits of such dimensions and character as we 

 now find. Whether the manganese was brought down entirely in 

 solution or only partially so, or entirely or partly in mineral com- 

 bination as fine muds from which the manganese was subsequently 

 dissolved, one cannot say at present. Both muds and solutions 

 probably have contributed the manganese which forms in great 

 part the deposits as we now find them. 



The conditions which brought about the formation of the car- 

 bonate and oxide of manganese are problematical. It is generally 



