BY THE REV. W. B. CLARKE, M.A., F.G.S., &c. 285 



M. Delesse mentions coal in Algeria, which was transmuted 

 from lignite by trap, but not coked, though enveloped by the 

 igneous rock which could not, therefore, have had very great heat. 



In England there, are numerous localities where coal beds are 

 altered just in the same way. In 1838 I visited a spot in 

 Radnorshire, where such was the case, and here is a portion of 

 the transmuting basalt. In the Isle of Anglesea the coal also is 

 coked and becomes incombustible when near Dolerite. 



Various minerals are introduced into coal by transmuting 

 agents, oftentimes by water impregnated by earths and salts. 



Thus iron, sulphur, lime, manganese, magnesia, alumina, and 

 even quartz itself are found in abundance, sometimes crystallised. 



Mr. Gould found a particle of gold in coal in Tasmania, and 

 in this specimen of coal from New Caledonia you can perceive the 

 crystals of quartz studding the laminae. Sir R. Murchison has 

 mentioned a similar occurrence in the coal of Barrow Hill, near 

 Dudley. (Sil. Syst. p. 497.) 



In fact, minerals of all kinds are found in some Coals, natural 

 Cokes, Anthracites and Graphites. 



That this latter is an evidence of the influence of igneous action 

 may be acknowledged, when we consider that the great plumbago 

 mine of Borrowdale, in English Cumberland, is in the midst of 

 a trappean mass passing through Silurian slates. Another 

 instance of the alteration of coal beds in contact with trap passing 

 to basalt, occurs at Dudley, where the shales are converted into 

 jasperoid porcellanite (as in Trinidad, and on the Hunter). 

 There is especial mention of this in Murchison's " Siluria," where 

 the author compares the altered shales to the " brand-erde " of 

 the Germans. 



With two or three further remarks I will dismiss this part of 

 the subject. 



I have previously given my reasons for believing that the 

 Hawkesbury rocks near Sydney had been subjected to transmu- 

 tation, arguing from the crystalline particles. I see also an 

 additional argument in the fact that these rocks are full of little 

 bits of graphite, which are so perfect, that in my explorations I 

 have sometimes picked them out with a knife to serve for a 

 pencil when I happened to have no better one at hand. 



T 



