GENERAL GEOLOGY. 



B)' PROFESSOR RALPH TATE and J. A. WATT, B.Sc. 



(With Plates 1 and 2). 



The geological features of that portion of Central Australia examined by us, 

 embracing the country lying between Oodnadatta on the south and the ranges 

 on the north, will be descriljcd under a number of headings. Under each of 

 these, bearing the names of the geological systems to which the different series 

 of rocks are assigned, a summary of the conclusions of previous observers and an 

 account of the general geological features, the extent, thickness, mineralogical 

 composition, petrological cliaracters, and fossiliferous contents of the rock will be 

 given. Detailed descriptions of the fossils and of the microscopical characters of 

 the more important rocks form the subjects of separate papers. 



I. — Previous Recopds and References to the Literature of 



the Region. 



I. — Waterhouse, F. G., "Features of Country on Stuart's Track across 

 Australia," Pari. Paper, S. Aust., No. 12"), 186,3. The author was naturalist to 

 Stuart's Transcontinental Expedition, and in his I'eport makes incidental refe- 

 rences to geological features. He divides the country into : — 



(1) The spring and salt-bush country extending from the Goolong Springs to 

 a little north of Hanson's Gap (lat. 27°, 18', 23"). The springs are stated to be of 

 volcanic origin (pp. 1, 3, 4), and as proceeding from volcanic lava and extinct 

 cones. Reference is made to the discovery of the remains of Diprotodon australis 

 at Hergott Springs (p. 2), and of fossil shells in an argillaceous rock, attributed to 

 the Tertiary age, at the Gregory and Welcome Springs (p. 2). [This formation is 

 now known to belong to the Rolling Downs system, and the mussel-shells alluded 

 to are Modiola irifiata, Moore.] 



(2) This division extends to the southern side of Newcastle Water (lat. 17°, 

 36', 29"), and is described as somewhat sandy and occasionally stony and loamy 

 soil, with some considerable range of hills (p. 5). A geological section on the 

 banks of Finke River at Polly Sj)rings, near Engoordina, is described in the 



