'914-] CONCEPTION AND TRINITY BAYS, NEWFOUNDLAND. 373 



II. GENERAL GEOGRAPHIC AND GEOLOGIC RELATIONS OF THE 



MANGANESE DEPOSITS OF SOUTHEASTERN 



NEWFOUNDLAND. 



Geographic Relations. 



The manganese deposits here considered are located in the south- 

 eastern part of Newfoundland in the vicinity of Topsail, Manuels, 

 Long Pond, Chapel Cove, and Brigus on Conception Bay, and at 

 Smith Point on Trinity Bay. Manganese is also said to occur near 

 Ships Cove, Placentia Bay. The accompanying map, Fig. i, shows 

 the approximate location of these deposits. 



General Geology. 



The sedimentary rocks of this area are included in the Cambrian 

 and Ordovician systems and may be seen on the map (Fig. i) to 

 occur as irregular patches, the Ordovician composing the larger 

 islands of the bays and the Cambrian occurring as irregular and 

 widely separated fringes resting on the pre-Cambrian of the main- 

 land. The whole series consists almost wholly of shales and thin- 

 bedded sandstones with some limestones, and in the base of the 

 lower Cambrian an occasional conglomeratic bed. 



The iron ores of Great Bell Island are Arenig while the manga- 

 nese and their associated green and red shales are of late lower 

 Cambrian. 



Wherever the Cambrian strata have been found in contact with 

 the pre-Cambrian an unconformable relationship exists. The pre- 

 Cambrian rocks of this area as classified by Dr. Walcott (2:219) 

 and by Messrs. Murray and Howley (18: 141-154) respectively are 

 as follows : 



Walcott Murray and Howley 



Random 



r Signal Hill Avalonian 



! Momable 

 Avalonian -i --r ■, 



I.orbay 



[ Conception Huronian 



Laurentian Archaean 



The Avalonian and Huronian of Mr. Flowley represent a thick- 

 ness of 12,370 feet. A later unpublished estimate of 18,250 feet has 



