12 T. W. E. DAVID. 



As regards prevalent strikes of folds in the sedimentary 

 rocks and schistose structure in the gneisses and schists 

 at the Porongorup Range near Albany, the massive gneisses 

 are foliated in a direction N.W. to S.E. This trend is fairly 

 constant amongst the older crystalline rocks of the southern 

 part of West Australia, The three anticlines of the Stirling 

 Range strike approximately parallel to the major faults 

 which bound that range, the general trend being from 

 W.N.W. to E.S.E. Mr. Maitland considers that the folding 

 force has in this case operated from the south northwards. 

 Further north, as in the Ooolgardie and Kalgoorlie gold- 

 fields, the strike of the foliation and bedding is more 

 meridional being about N.N.W. and S.S.E. 



At Northam the trend of gneissic foliation is N.W. to 

 S.E., while that of the quartz-dolerite or quartz-diabase 

 dykes is chiefly from S.W. to N.E. Prom the Murchison 

 through Cue to Leonora, the trend lines in the older rocks 

 are still a little W. of N. and E. of S. 



The same remark applies to the great auriferous belts. 

 According to Mr. Maitland's views, these consist of highly 

 inclined metamorphic and sedimentary rocks associated 

 with contemporaneous interbedded eruptive rocks. Some 

 of these are distinctly amygdaloidal, and there is every 

 reason to believe them to be ancient lava flows. These, in 

 Mr. Maitland's opinion, have been infolded in great 

 synclines, amongst the gneisses, and have been subsequently 

 intruded by newer rocks such as serpentines, quartz- 

 dolerites (quartz-diabase), acid-porphyries, and granites, 

 the last intersected still later by greenstone dykes. 



According to Mr. Maitland's view the great gold belts 

 of Western Australia would therefore present some such 

 an appearance as is shown diagrammatically on Pig. 4. The 

 other alternative seems to be to regard these belts as 

 overthrust, rather than as overfolded areas. There can be 



