44 NOTES AND EXHIBITS. 



Professor David contributed the following " Note on the occur- 

 rence of the mineral sphene (titanite) in the granite from the 

 water-works tunnel, Bathurst " : — 



In the last edition of his work on the Minerals of New South 

 Wales, p. 85, Professor Liversidge, F.R.S., refers as follows to 

 the occurrence of a single isolated specimen of the above mineral : 

 ^' Sphene. A calcium silico-titanite. Crystallises in oblique 

 system. I have met with but one well-crystallised specimen, of a 

 green colour ; the locality in New South Wales from which it 

 came is uncertain." The Rev. J. Milne Curran, F.G.S., in his 

 paper on the Geology and Petrography of Bathurst [P.L.S.N.S.W. 

 Yol. vi. (2nd ser.)] has mentioned the occurrence of sphene in 

 granite at Mt. Stewart, near Bathurst. 



The author about two years ago collected some specimens of 

 granite from the tunnel driven partly under the bed of the 

 Macquarie River from the bottom of the well-shaft at the 

 Bathurst water-works. On examining one of these specimens 

 lately, at the Laboratory of the Geological Department at the 

 University of Sydney, the author has observed that it contains 

 well-formed crystals of sphene in tolerable abundance. 



The crystals of sphene in this granite are of a brown colour 

 seen by reflected light, and by transmitted light are of a honey- 

 yellow to reddish-yellow colour. In shape under the microscope 

 the sections of the crystals appear as acute-angled rhombs or 

 prisms, terminating in sharp ends. Each crystal is surrounded 

 by a dark zone, as seen under the microscope by transmitted light, 

 due to its high index of refraction, and the surfaces of the sections 

 have a somewhat rough pitted appearance. The pleochroism is 

 not very strongly marked, and the mineral does not polarise in 

 bright colours, but remains of a somewhat greyish tint under 

 crossed nicols. Near the centre of one large crystal there are 

 abundant enclosures of an opaque black mineral, which is probably 

 titaniferous iron. The cleavage is somewhat strongly marked. 

 The mineral dissolves slowly in sulphuric acid. 



It appears to have been one of the earliest minerals in the 

 granite to separate outj as most of the other minerals are moulded 



