128 Coal-Seams of Van Diemen's Land. 



by the fact that about half a mile above the first crop, after 

 passing over a small anticlinal axis, we again come on the 

 Coal in its original thickness dipping up the stream, or 

 nearly north, at an angle of 7°, the intermediate portion of 

 the arch having been denuded with the Coal along the river 

 channel. Vide PL III., fig. 2. 



This seam would, taking the cubic foot at 56 lbs., and not 

 allowing for loss in working, yield about 5,200,000 tons per 

 square mile. 



On either bank of the stream the beds are overlaid by 

 large masses of greenstone, which have fallen or been trans- 

 ported from the surrounding high peaks and ridges : this 

 greenstone drift at several points along the course of the 

 river has been cut through to a depth of 30 or 40 feet, and 

 I have no doubt it often attains even a much greater thick- 

 ness. 



It is universally distributed along the flanks of all the 

 higher ranges, extending from the solid greenstone which 

 usually forms their summits nearly to the sea level, and thus 

 almost invariably concealing the actual junction of the 

 latter with the beds of the carboniferous series, which are 

 seldom exposed on the surface except in the river channels, 

 where the overlying drift has been cut through, or on the 

 sea-beach. 



Besides the seams already noticed, several other smaller 

 ones occur, associated with beds probably above those sunk 

 through in the Company's works. 



The crop of one, if not two, of these is partly exposed in 

 a cutting on the tramway about three quarters of a mile 

 south from the " New Coal Shafts," marked in the accom- 

 panying plan. 



Again, at three points in the banks of the Denison Eivulet 

 seams of Coal are seen cropping. 



