9i On the Geology of Nexocastle in Australia. 



sea. The other side of the difFs inland, is found to contain 

 large blocks of petrified wood, of a grayish-white colour 

 passing into brown. About two miles from this spot towards 

 the point {b\ at the base of the cliff's may be seen large por- 

 tions of the trunks of petrified trees, which have been detached 

 from the heights above; and which upon being broken pre- 

 sent a deep black appearance, capable of a very fine polish: 

 the bark of the wood, which is exceedingly compact, and 

 not easily fractured by the hammer, being of a grayish-white. 

 Petrified wood in ironstone and hornstone, and traversed by 

 fine veins of chalcedony, in some specimens beautifully cry- 

 stallized, is found from two to three miles inland from the 

 coast, lying scattered about in large blocks over the ridges, 

 covered with thick and unfelled bush, and on the sides of the 

 gullies and deep ravines, from the bottom of which arise the 

 stately Cabbage Palm and the Gigantic Fern, the former from 

 60 to 90, and the latter from 20 to 30 feet in height, towering 

 amidst the surrounding dark-green foliage, and giving to these 

 secluded spots all the fascination of an Oriental picture. 



But the most remarkable feature in the cliffs on this part 

 of the coast is the circumstance of their having been in a state 

 of combustion in three several places : viz. at the points b, c, and 

 d; at the point/; recently, and at the others evidently at no di- 

 stant period. The point [b) of these cliffs had been frequently 

 observed, by the crews of vessels passing from the port of New- 

 castle to Sydney, to emit a considerable quantity of smoke- 

 But as it was concluded that the fire, from whence the smoke 

 proceeded, was occasioned by the native blacks, who had, as 

 they term it, " sat down " there, to collect fish from the water 

 left by the receding tide amongst the rocks, no particular 

 notice was taken of the circumstance: and it was only in the 

 early part of the year 1830, that it was accidentally disco- 

 vered that such was not the case; but that sulphureous va- 

 pours, of a very strong and pungent nature, accompanied in 

 some portions of the spot under combustion by brilliant flame, 

 were evolved from several crevices in the cliff", the margins 

 of which were covered with volcanic sal-ammoniac, of different 

 shades of colour; in efflorescent crusts, small botryoidal; and 

 in beautiful crystals intermingled with sulphur. Upon my 

 visiting this spot in the month of August last, I found, how- 

 ever, that the fire was then entirely extinct, some convulsion 

 having evidently taken place, the cliff" having separated, and 

 the materials from above having as it were fallen in upon the 

 burning portions, and extinguished the fire. In the same 

 month also, I discovered that the cliff' at the point (c) had at 

 no distant period been on fire, presenting in its extinguished 



