THE YOLCANIC ^ROGKS OF SPRlNdSlIRE. 

 CENTRAL QUEENSLAND. 



By H. C. Richards, D.Sc, Lecturer in Geology, The 

 University of Queensland. 



(With 1 Plate and 6 Text-figures). 



{Bead before the Royal Society of Queensland, 2Sth October ^ 



1918.) 



— Page 



179 

 180 

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 185 

 186 

 187 

 189 

 192 

 19a 

 195 

 197 



Introduction 

 Previous Literature 

 Physical Features 

 Palaeozoic Sediments 

 Petrography of Volcanic Rocks 



Lower series 



Middle series 



Upper series 

 Chemical Characters of Volcanic Rocks 

 Relationships and Origin of Volcanic Rocks 

 Age of Volcanic Rocks 



Introduction. 



In August, 1917, the writer visited Springsure for the 

 purpose of examining the reported occurrence of alunogen 

 on Vandyke Holding, sixteen miles south-west of Springsure^ 

 and also the volcanic rocks in the area, some of which were 

 reputed to be alkaline trachytes. 



The result of investigation of the alunogen deposit 

 is given elsewhere in these Proceedings while the treat- 

 ment of the volcanic rocks in particular is dealt with in this 

 paper. 



The area has been spoken of for some time past as 

 containing representatives of the Cainozoic alkaline trachytes 

 and as far as the author knows these rocks have not been 

 examined and described hitherto. 



The Agricultural Chemist (Mr. J. C. Brunnich, F.I.C.) 

 kindly arranged for one of his assistants, Mr. G. R. Patten, 



