120 VOLCANIC AREA OF EAST MORETON, ETC., DISTRICTS, Q., 



and shows pleochroism in tints from light green to bluish-green. 

 It is allotriomorphic and apparently an alteration product of 

 uralite. The uralite is secondary after some pyroxene no longer 

 present. The magnetite is partly idiomorphic and party allotrio- 

 morphic and dusty, inclosed in uralite and hornblende. 



(4) Affinities. — This rock is apparently an altered gabbro which 

 has had its augite changed to uralite and its felspar rendered 

 more acid by the infiltration of silica-bearing vapours. The 

 banded arrangement of the constituents is probably due to the 

 original schlieric structure in the gabbro. The rock should be 

 called Quartz Epidiorite. 



Remarks. — Several other slides from this locality were 

 examined, and were found to contain the following minerals : — 

 plagioclase, orthoclase, quartz, uralite, augite and biotite. 

 Many were banded; in some the bands were medium-grained, in 

 others fine-grained. I look upon these epidiorites as having been 

 probably derived from the same magma as the greenstones, 

 glaucophane schists and amphibolites intruding the schists around 

 Mt. Mee and Woodford. Their alteration was probably effected 

 by the great Carboniferous granite intrusion, which probably also 

 introduced the gold and silver of this district. The magma 

 which gave rise to these rocks was of the gabbro composition, 

 and rocks like gabbro, peridiotite, quartz gabbro quartz- diorite, 

 and pyroxenite might have differentiated from it. The amphi- 

 bolites of the D'Aguilar Range seem to be altered pyroxenites, 

 and the serpentines altered peridotites, so all these varieties are in 

 reality represented. 



In Mr. Newman's collection I find, also, a dark rock labelled 

 " Blacks' Reserve, Woodford," which contains quartz, orthoclase, 

 hypersthene, biotite, magnetite and andalusite. It has a gneissic 

 structure, and ma}' be termed " hypersthene-andalusite gneiss." 



Sp. No. 95. Granite. Loc: Cooran, from railway cuttings 



immediately west of railway station. 



This rock is very weathered, and might easily be mistaken for 



sandstone. Some authors would call this rock arkose. I prefer 



to use that term for rocks that have been formed by the total 



