245 



are signs which point to the conclusion that the topography 

 of the present day in some measure reflects that of early 

 Carboniferous time. 



The nearness to the old shore of the portion of the 

 Carboniferous basin still preserved doubtless, in part at 

 least, explains the great volume and general characters of 

 the sediments. Possibly a considerable proportion of the 

 supposed thickness may be explained as due to dip of de- 

 position. 



The general similarity of the Carboniferous measures 

 as displayed in Cape Breton, to those on the mainland of 

 Nova Scotia and over New Brunswick, along the southern 

 and western edge of the Gulf of St. Lawrence; the resem- 

 blance of these beds to those developed in Newfoundland 

 on the east side of the St. Lawrence gulf; and the occur- 

 rence of Carboniferous strata on the Magdalen islands 

 situated towards the centre of the hydrographic basin, 

 have lead various observers to believe that the Sydney 

 Carboniferous area represents a remnant of the southern 

 border of a once continuous basin of Carboniferous strata 

 that may have occupied the greater part of the area of the 

 Gulf of St. Lawrence. 



The Carboniferous section of the Sydney field is custom- 

 arily divided into the following groups, tabulated in 

 descending order with approximate thickness as developed 

 in the vicinity of Sydney harbour. 



Productive Coal Measures i,970 feet (600-5 rn-) 



Millstone Grit 3,625 feet (1,105-0 m.) 



Limestone series 4, 500 feet (1,371 -6 m.) 



Conglomerate series 2,525 feet (769-6 m.) 



Total 12,620 ft. (3,846-7 m.) 



The Conglomerate series consists essentially of red 

 conglomerates, sandstones and shales. The conglomerates 

 predominate and their waterworn pebbles and boulders 

 are often of large size. Calcareous material in places 

 forms the matrix of the conglomerates and occasional 

 impure beds of limestone occur. 



The Limestone series includes a great thickness of 

 sandstone and shales, red and grey or green in colour, 

 also conglomerate horizons, and many beds of limestone 

 that frequently are fossiliferous. Only one bed of gypsum 



