251 



ABSTRACT OF PROCEEDINGS 



OF THE 



Royal Society of South Australia 



(Incorporated) 



for 1909-10. 



Ordinary Meeting, November 2, 1909. 



The President (J. C. Verco, M.D., F.R.C.S.) in the 

 chair. 



Exhibits. — Mr. E. Ashby exhibited birds from Lake 

 Frome, viz., Stiltia Isabella, Artamus personatus, Psephotus 

 xanthorrhous , also a possibly new Acanthiza ; from the River 

 Murray, above Mannum, Epthianura tricolor (Gld.), a rare 

 Southern visitor, and its nest and eggs ; Myzomela nigra, with 

 nest and eggs ; also a long series of birds from North-Eastern 

 Tasmania. Mr. Ashby also exhibited samples of tin ore, 

 occurring in rocks, probably of Silurian age, in Tasmania, 

 and supplied the following notes in relation to the same : — 

 "We believe the discovery of the occurrence of tin in Silurian 

 rocks is very rare, or possibly unique, and is, therefore, of 

 considerable scientific interest. The mine known as the Great 

 Pyramid is situated about six miles from Scamander, on the 

 north-east coast of Tasmania. The rocks are described as 

 Silurian in the Government geological maps. As far as we 

 are aware, the nearest granite would be some miles away. 

 The tin occurs in quartzite beds, in a steep anticline of folded 

 slates and quartzites. The hill is about 500 ft. high above 

 the River Scamander. On the north side the superincumbent 

 beds have been denuded, and a bed of quartzite has been 

 exposed which, where penetrated by the north adit, is 30 ft. 

 thick. This quartzite bed has been broken into and sampled 

 on the north side over a longitudinal length of 1,000 ft. and 

 a vertical width of 100 ft. by means of deep trenches blasted 

 out of the solid rock. Something of the probable commercial 

 importance of the discovery may be inferred from the fact 

 that the average result of this sampling shows the metallio 

 tin contents of this quartzite bed to be fully 1 per cent. On 

 the south side of the hill, several of the beds on folds that 

 have been eroded from the northern side still exist on the 

 bulging portion of the hill. While the beds, or folds, of slate 



