30 



No. 1. Analysis of a Wimmera specimen made by the late 

 ^ J. Cosmo Newbery, and published in the Melbourne 

 Exhibition Catalogue, 1866. 



No. 2. Analysis of a specimen from Uralla, N.S.W., made last 

 year by Mr. J. C. H. Mingaye, and forwarded to me 

 by the courtesy of Mr. E. F. Pittman, Government 

 Geologist of that colony. 



No. 3. Partial analysis of a specimen from Mount Elephant, 

 made by Mr. F. Stone, Assayer to the Mines Depart- 

 ment. 



No. 4. Partial analysis made by the author of a specimen from 

 Central Australia, collected by Professor Spencer. 



The silica percentages shown by these analyses should prove 

 indisputably their acid nature ; even No. 2, with its lower silica 

 contents, makes it an undoubted glassy representative of the 

 trachyte series. The term acid is now used, not perhaps in its 

 generally accepted sense, but only in contra-distinction to basic, 

 which includes eruptives carrying up to about 55 per cent, 

 silica. As a matter of fact, ib seems probable that a number of 

 specimens belong to the intermediate series. Mr. George "NV. 

 Card, Curator of the Geological Museum, Sydney, has pointed 



