1823.] Mr. Winch on Specimens of Rocks, Sec. 341 



Article III. 



Account of some Specimens of Rocks, fyc. from Van Dieman's 

 Land, and from New South Wales. By N. J. Winch, Esq. 

 Hon. MGS. 



(To the Editor of the Annals of Philosophy .) 



SIR, Naccaslle.ujwn-Tyne, March 27, 1823. 



The Literary and Philosophical Society of this place has 

 lately been presented with a considerable number of minerals by 

 the Rev. T. H. Scott, of Whitfield, collected by himself in Van 

 Dieman's Land and New South Wales, during his travels in 

 those distant regions. And notwithstanding duplicate speci- 

 mens, and probably many which were not duplicates, had been 

 given to the Universities of Cambridge and Oxford, and the 

 Geological Society of London, still we possess a sufficient num- 

 ber to throw considerable light on the structure of Australia. 

 By many theorists it has been conjectured that these lands are 

 of more recent formation than those of the other parts of the 

 globe, but with how little justice such an opinion has been 

 adopted, the following brief description of some of the best 

 defined species of our collection will evince. 



From Van Dieman's Land. 



1. A hard slaty sandstone of a pale-brown colour with 

 impressions of flustras, resembling those of Humbledon Hill, 

 near Sunderland. Pectenites, and some other species of bivalve 

 shell, in size and shape like a hazel nut. From a hill near 

 Hobart's Town, 800 feet above the level of the sea. 



2. A very fine grained white sandstone. Near Hobart's 

 Town. If in sufficient quantity, this must be a valuable material 

 for the purposes of building. 



3. Coal, of the same species i\s the Newcastle coal. From 

 Adventure Bay, eight miles distant from Hobart's Town. 



4. Black bituminous shale, with spangles of silvery mica, and 

 slight impressions of the leaves of some phaenogamous plant. 

 Above and below the coal at Hobart's Town. 



5. Limestone, of a brownish-grey colour, compact texture, and 

 splintery fracture, with veins of white quartz. Eight miles 

 north-west of Hobart's Town. Not unlike some of the beds in 

 our encrinal limestone formation. 



6. A bluish grey trap rock, resembling the blue millstone 

 rock of Andernach on the Rhine. Its structure is cellular, the 

 cells containing minute globules of black obsidian, occasionally 

 coated by a thin pellicle of iron ochre, owing to decomposition. 

 The rocky part is easily reduced to a black slag, by the action 

 of the blowpipe, and with the addition of borax, melts into a 

 pale green glass filled with air bubbles. The obsidian is reduced 

 with difficulty into a brilliant black glass. Masses of this rock 



