'01 



NOTE ON A GLAUCOPHANE SCHIST FROM THE 

 CONANDALE RANGE, QUEENSLAND. 



By H. I. Jensen, B.Sc, Linnean Macleay Fellow of the 

 Society in Geology. 



Last year, on a trip to Queensland to review the field geology 

 of the East Moreton District prior to the publication of my 

 paper dealing with that area, (These Proceedings, 1906, p. 73) I 

 went from Woodford, on the Stanley River, across the Conandale 

 Range to the headwaters of the Mary River. 



On the ' Postman's Track,' at the foot of the range on the 

 Mary River side, there is a quartz reef bearing a trace of gold 

 running across the track. It intrudes highly metamorphic and 

 foliated schists and phyllites. Close to the reef, and interbedded 

 with the other metamorphic rocks, there is a body of dark, blue- 

 black schist, having a silky lustre and true schistose fracture. 

 This rock struck me at once as being an interesting amphibolite 

 schist, and I accordingly took a specimen. A few hundred yards 

 further along the road, I met with a highly interesting mass of 

 felspar porphyry intruding the metamorphic series. This rock 

 has no relationship with the schists in question, but is closely 

 related to the porphyrites at Point Arkwright and Noosa Head, 

 on the coast. It is, in fact, a granophyric porphyry containing 

 albite, orthoclase, quartz, augite, and hornblende, and belongs, 

 therefore, to the monzonitic series. The structure and composi- 

 tion of this rock bring out its affinities with the Post-Triassic 

 porphyries so strongly that it gives one good reason to believe 

 that most of the granites of the Yabba Ranges, which belong 

 to the same monzonitic class, are of Post-Triassic age. 



If most of the granites are Post-Triassic, it is easy to compre- 

 hend that rocks as young as Carboniferous (to which age all the 

 East Moreton schistose rocks are referred by Jack) or Devonian 

 (as Gregory terms them) have been foliated and metamorphosed 

 as highly as the Archaean rocks of other parts of the world. 



