metamorphic rocks of s.e. queensland. 259 



2. Summary of Rock Types Represented in the Area. — 



A. Igneous — 



I. Plutonic. 

 Rock Family. Chief Localities. 



la) Granite ... ... ... Cooran, Woondum tableland, Beenam 



Range, Obi-Obi, Woodford, Delaney 

 Creek (Black's Range), Leacy's Creek. 

 (h) Syenite ... ... . . Woondum tableland. 



(c) Diorite Porphyry ... ... Noosa Heads, Point Arkwright, Mary 



River. 



(d) Gabbro and Amphibolite ... In some Gympie mines. 



II. Volcanic. 

 (a) Rhyolite ... ... ...Mount Archer, Toolburra Range, 



Nindherry, and railway cuttings near 



Nambour. 

 (6^ Comendite and Trachyte ... Localities given elsewhere. 

 \c) Andesite ... ... ... Yandina. 



\d) Basalt ... ... ... Blackall Range, Woondum tableland. 



Mount Mee. 



B. Sedimentary — 



L The Gympie beds, which have been so altered, that they might 

 well be treated as metamorphic rocks. 



2. The Trias-Jura system, consisting of sandstones, conglomer- 

 ates, clay shales, carbonaceous shales, and coal. 



3. Recent alluvium. 



c. Metamorijliic Rocks, comprising — 



1. Gympie system, at Gympie, Chinaman Creek, Wararba, &c. 



2. Gympie (Carboniferous) or older, much more highly metamor- 

 phosed, rocks. These rocks are provisionally considered Gympie by 

 the geological survey, but for reasons which I will give on the follow- 

 ing pages I am inclined to regard them as much older. 



3. Relationship of the Ipswich and Burrum Beds. — As already 

 emphasised in one of my papers,* there is no stratigraphical break 

 between the Ipswich and Burrum beds. They merge into one another 

 at Point Ai'kwright without any apparent unconformity. They are 

 probably quite identical in age. 



4. The Gympie Beds. — In this paper no attempt will be made to 

 describe the stratigx'aphy of Gympie, a work with which the geological 

 survey is proceeding at present, but the petrological characters of 

 some of the more well-known Gympie rocks will be described, and 

 their origin will be traced. 



{a) Gympie General Geology. — The true Gympie rocks at Gympie 

 occupy an area about seven miles long, and perhaps five miles wide, 

 around which appear phyllites with an older facies. The chief rocks 

 represented in the series are known on the field as sandstone, con- 

 glomerate, slate, black rock, plumbago, greenstone, diorite, andesite, 

 greywacke, schist, and granite. Of these rocks the granite, diorite, 



* Geology of the VoleaTiic Area of the East Moreton and Wide Bay District.^, 

 Queensland. Proc. Linn. Soc, N.S.W. 1900. Part I, 



