DISTniCT OF CAPE BRETON COUNTY. 411 



undulations and striee, in such a manner as to give the appearance of 

 a pinnate leaf carved in high relief. At each side of these impressions, 

 and about a tenth of an inch distant from them, are interrupted lines, 

 in I'elief in the casts, and running parallel with the casts of the furrows. 

 Tiie whole has exactly the appearance of the track of the swimming 

 feet and edges of the carapace of a small Lhnulus^ or King-crab. 

 The tracks have also the same tortuous character with those of 

 the modern Limulus. Limuli have not yet occurred in the Coal 

 formation of Nova Scotia, though they occur in rocks of this age else- 

 where ; but from these tracks I infer that animals of this kind lived 

 in the Sydney Coal-field, where their remains will probably hereafter 

 be found. I have proposed for these impressions the name R. Aca- 

 dicus^ in a paper on footprints of this class in the "Canadian Naturalist." 



Useful Minerals of the Carboniferous District of Cape Breton County. 



Coal ranks at the head of these, about 421,000 tons being raised 

 annually from the coal beds of this district. The oldest colliery in 

 the district is that of North Sydney, which is worked by the General 

 Mining Association, on the north side of Sydney Harbour. The coal 

 is shipped at the bar at North Sydney, to which place a railway has 

 been laid. The coal from this mine is used principally for domestic 

 fires, and for the production of steam, for which it is admirably 

 suited. 



Of the thirty-four seams included in ]\Ir Brown's Sydney section, 

 only four are of workable thickness ; they are, — 



1. The Indian Cove seam, about 450 feet of vertical thickness 

 below the main seam . . . . . . 4 ft. 8 in. 



2. The main seam . . . . . . .69 



3. The Lloyd's Cove seam, about 730 feet of vertical 

 thickness above the main seam . . . .50 



4. The Cranberry Head top seam, about 280 feet above 

 Lloyd's Cove seam . . . . . .38 



Of these only the main scam is worked at present, at the North 



Sydney mines. It yields a bright, free-burning coal, giving out its 



heat very rapidly, and leaving a very small quantity of heavy reddi.sh 



ashes. According to Professor Johnston, it yields, — 



Volatile matter . . . 26-93 



Fixed carbon . . . 67*57 



Ashes ..... 5'50 



100-000 



