1914.] CONCEPTION AND TRINITY BAYS, NEWFOUNDLAND. 451 



mineral particle such as rhodochrosite or calcite as a nucleus, with 

 the formation of the nodule, there will be a decrease in the concen- 

 tration of the solution at the contact with the nodule which will be 

 accompanied by a reduction of surface tension. If we are dealing 

 with a liquid-liquid phase we would have a spherical nodule in which 

 case both liquids would be easily deformable and the surface would 

 tend to become a minimum. Our twofold phase, liquid-solid, or 

 threefold phase including the colloidal phase which probably plays a 

 part, only allows of deformability on the part of the liquid and 

 partial deformability on the part of the nodule. Under the bedded 

 conditions of this two or three fold solution, colloid and solid 

 phase the tendency of the surface tension to reduce the surface to 

 a minimum is well exemplified in the discoidal nodule. 



Spherules. — One of the characteristic features of this deposit 

 is the occurrence of hematite in spherule-like forms and larger, 

 roughly spherical aggregates. Fig. 26 illustrates the occurrence. 

 They differ decidedly from the spherules of the Wabana, Clinton, 

 and other typical oolitic iron ores in that they are less symmetrical 

 and are without any visible nuclei. These spherules are here de- 

 scribed as incipient in as much as they seem to lack full develop- 

 ment or to have been impeded in their growth. Such a retardation 

 of development might have arisen from their growth in clayey sedi- 

 ments which were still unconsolidated. 



Mineral Associations. — The three important mineral associa- 

 ciations of the manganese deposits of S. E. Newfoundland are 

 barite, tri-calcium phosphate and hematite which will now be con- 

 sidered with reference to their occurrence, association and genesis. 



Barite. — Barite is one of the most characteristic mineral asso- 

 ciations of the deposits under consideration as is often the case with 

 manganese deposits elsewhere in the world. It is particularly char- 

 acteristic of the Manuels, Topsail and Smith Point localities and 

 occurs in various ways. 



Barite is found in small veins crossing a cryptozoan nodule 

 showing quite clearly its epigenetic character so far as that par- 

 ticular portion of the bed is concerned. Fig. 23 (Slide 276) shows 

 a solitary crystal fragment of barite in a carbonate-oxide of man- 



