292 J. A. THOMSON. 



ON ROOK SPECIMENS FROM CENTRAL AND 



WESTERN AUSTRALIA. 



Collected by the Elder Scientific Exploring 



Expedition of 1891-2. 



By J. Allan Thomson, b.a., d.Sc, f.g.s. 



(Communicated by Prof. David, ba., c.m.g., f.r.s., Hon. D.Sc, Oxon.> 



[With Plate XIV.] 



[Read before the Royal Society of N. S. Wales, November 1, 1911.'] 



The rocks described in the present paper were presented 

 to Professor David by Mr. Richard Helms, the naturalist 

 of the Elder Scientific Exploring Expedition of 1891-2. 

 Through the kindness of the former gentleman the writer 

 was permitted to examine the collection and prepare the 

 following notes on the rocks. 



The expedition, well equiped by Sir Thomas Elder, crossed 

 from South Australia to the Murchison Goldfield in the 

 years 1891 and 1892. * A large number of rock specimens 

 were collected all along the route, and a brief account of 

 these, and of the chief geological features of the country 

 passed over has been given by Mr. Victor Streich. 2 The 

 rocks here described appear to be in some respects supple- 

 mentary to those listed by Mr. Streich. One of them 

 comes from Fraser's Range, E.N.E. of Norseman, W.A., 



1 Cf. Lindsay, D., Journal of the Elder Scientific Exploring Expedition. 

 1891-2. With Maps. Adelaide, 1893. 



2 Trans. Roy. Soc, South Austr., Vol. xvi, Part n, 1893, pp. 74-110; 

 also Stelzner, A. W., Supplementary Notes on the above named Collection 

 ibid., pp. 110-2. Tate, R., Appendix, List of Eock-specimens collected by 

 Mr. Wells, Second Officer, on a Journey east from Murchison Goldfield, 

 ibid., pp. ]13-5. Map of route showing position of camps and geological 

 formations, ibid., facing p. 236. 



