1866.] CLAKKE AtrSTEALIAN" CANNELS. 441 



seams and porphyry, the volatile matter should be dispersed, and not 

 accumulated ; and the alteration of the combustible into anthracite 

 or graphite would be the most probable eifect*. The association of 

 porphyry and cannel coal is therefore merely accidental, and, so 

 far as my experience goes, has no bearing on the condition of the 

 latter. Assuming, even, that the CoUey-Creek cannel is in the 

 Lower Coal-measures, the arrangement is not much affected thereby, 

 for they rest upon and are younger than the porphyry. Supposing 

 heat to be necessary to produce the natural distillation required for 

 saturation of deposits in situ, there is no need to infer that the sup- 

 posed (always much exaggerated) heat of granitic rocks at the time 

 of eruption can have had anything to do with it. It is a fact also 

 that the inflammable cannels are limited in area, and oftentimes 

 pass oif into an ordinary coal. The most that can be reasonably 

 conjectured on such a change is, that (supposing no objections to arise 

 from other principles) the volatile matters removed by distillation, or 

 in the change to anthracite, from one part of a seam to another part 

 of such a seam, have found a reception where no revolatilization could 

 occur. But there is no evidence to be obtained of any such transfer. 

 The condition of Loder's cannel would imply that it had originally 

 been deposited in a marshy hollow of the Carboniferous period, to 

 which drift quartz and arenaceous sediment had access. The grains 

 of quartz are certainly entangled as they would be in a muddy or 

 viscid substance. 



The yield of the CoUey- Creek cannel is 60 gallons per ton. 



4. Illaivarra Shales. — Under the escarpment at the head of the 

 Cordeaux River and a little to the west of it, and below Mount Kemble, 

 in the beds intersected by American Creek, a series of shales exist 

 with coal, a portion of which are found to produce oil, but in incon- 

 siderable quantity compared with the Brown Cannels. These schist- 

 ose beds are arenaceous in appearance, and when taken from the 

 retort, after distillation, are found in lumps of charcoal, not coaked, 

 but with a ligneous character. They will perhaps not be esteemed 

 as a source of oil. With them are also schists that have a half 

 anthracitic or graphitic texture ; and a long way below their level, 

 which is from 900 to 930 feet above the sea, the shales of the locally 

 lower coal-seams, not far above the junction with the Upper Marine 

 beds, are altered by basalt, which has also coked and prismatized the 

 coal in the Bollambi seams. Here, then, though there is some evi- 

 dence of oil-bearing schists, we find that character not prominent in 

 association with igneous rocks, but, on the contrary, the anthracitic 

 and graphitic characteristics are well established. 



The lUawarra Coal-measures are nearly the uppermost of the New 

 South Wales series of coal-bearing beds, being certainly above the 

 Newcastle series, and they extend for at least fifty miles, passing 

 upwards to the level of the Nattai or Fitz Roy beds in their exten- 

 sion southwards. 



Some blocks from American Creek have been taken out, which are 

 cut very easily with the knive, leaving a clay-like surface, and hav- 

 "* See Delesse, Metamorphisme des roches, pp. 305-314. 



2n2 



