THE CAUnONIFEROUS. 41 



western end of this part of the trongh, that nearest the East River, 

 no important extension of the great seams of the Albion mines appears 

 yet to have been distinetly recognised, though these seams, or their 

 equivalents, must exist both on the south side towards jNl'Lellau's 

 brook, and on the north side near New Glasgow (see the map, Ac. 

 Geol., p. '620). The beds of coal wliich have been worked near the 

 east side of the East River, the Foster and Lawson seams, are 

 believed to overlie the great main seam by a thickness of about 1500 

 feet. In the eastern half of the trough these upper beds are appa- 

 rently represented by the Marsh Brook seam, the George iM'Kay 

 seam, and associated beds ; and the correspondence of the beds and 

 their containing measures, as well as in the quality and structure of 

 the coal, .seem to establish this equivalency. But here, at a distance 

 of 480 yards to the rise, occurs the M'Bean seam, now worked in the 

 Vale Colliery, and associated with other seams, making in all so 

 great an aggregate of coal, that they may not unreasonably be 

 regarded as the equivalents of the main seam. In this case, how- 

 ever, the thickness of the overlying measures must have diminished 

 or been concealed by faults, and on that account it is still possible 

 that the real equivalents of the main seam may occur lower down. 

 The M'Lean beds, not yet worked, lying to the westward of the 

 explored part of the M'Bean seams, may in the one case be the con- 

 tinuation of the M'Bean series, or in the other may be much lower. 

 There can be little doubt that these M'Lean beds represent the main 

 seam. The great inequality of the original deposits in this Coal- 

 field, and the di.-turbances to which they have been subjected, with 

 the absence of good natural sections, oppose great obstacles as yet to 

 the decisive settlement of these questions — the answers to which 

 are, howevei', being gradually worked out by mining explorations. 



In 1868, immediately after the publication of my second edition, I 

 had an opportunity to examine some parts of the coast of Cape 

 Breton, and more carefully to correlate the Coal-beds of that region, 

 as well as to make some important observations on fossil plants. 

 These observations have not been published in full, but in the same 

 year I sent a note relating to them to tlie Nova Scotia Institute, 

 which was printed in their Transactions, and gives my views on these 

 subjects as formed at that time. 



The following section of the Coal formation, as exposed on the 

 south side of Sydney Harbour, on the property of the Victoria Mining 

 Company, is coiulcnsed from observations made with the aid of Mr 

 Ross, of the Victoria Mine, and Mr Mosely of Sydney. The order 

 is descending. 



