MINEEALOGICAL NOTES — ANDERSON. 



89 



BARITE. 



Barite has for some time been known to occur at several points 

 in the Triassic area in the neighbourhood of Sydney, both in the 

 Hawkesbury Sandstone and in the succeeding Wianamatta 

 Shales. It was first recorded by Mr. H. G. Smith who found it 

 in a quarry near Cook River, five miles west from Sydney, in 

 small well-formed crystals, consisting of almost pure barium 

 sulphate with a trace of calcium.^ Subsequently barite was found 

 near Gosford Railway Station." It has also been observed by 

 Prof. T. W. E. David, Trustee, at Five Dock, associated with 

 quartzite and in close })roximity to a decomposed basalt dyke. It 

 is found under similar conditions at Pyrmont Sandstone Quarries, 

 and at Pennant Hills Quarries it occurs as veins in the basalt at 

 a depth of over fifty feet. Pi'of. David believed that the barite 

 found in the Sydney area originated pi-obably from the basalt, 

 numerous dykes of Avhich traverse the sedimentary rocks.^ 

 He informs me, howevei', that he has now modified 

 this opinion since observing how widespread is the dis- 

 tribution of barytes in the Pcrmo-Carboniferous sedimentary 

 rocks of the Northern and Southern Coal-fields as well as in the 

 Triassic strata of New South Wales. He now atti'ibutes the 

 liarite of the Sydney area chiefly to decomposition of detrital 

 barytic felspars. Specimens from Macdonald Town and Thirlmere 

 are in the Australian Museum collection. 



» Smith— Proc. Liiiu. Soe. N. S. Walep, (2), vi., 1892, pp. 1.31-1:52, 



« Baker— ioe. cit., (2), vii., 1893, p, 328, 



' David — Journ. Roy. Soc. N. S. Walee, xxvii., 1894, p. 407. 



