10 T. W. E. DAVID. 



As already stated by Mr. Maitland, the faults bounding 

 the Collie Coal-field 1 are probably continuous with those 

 which have given origin to the Stirling Range. 2 Mr. Mait- 

 land states in regard to the Stirling Range that lateral 

 compression has worked from the south, and has formed 

 three anticlines in a distance of ten miles. Mount Tool- 

 brunup, the highest point in the range is nearly 4,000 feet 

 above sea level. A prolongation of these faults to the 

 B.S.E. runs through Cape Riche. The soutliern of these 

 two faults, or perhaps zone of faults, has a throw of approxi- 

 mately the order of 2,000 feet. 



In regard to the rift valley of the west coast, the sharp 

 trend northwards of the Murchison River close to its mouth, 

 and the remarkable coastal indents near Shark Bay are 

 very suggestive of a prolongation of this rift valley in that 

 direction. The probable geological structure of this rift 

 valley are shown on Figs. 1 and 2, and that of the Collie- 

 Stirling fault zone on Fig. 3. 



Fig 3. Diagrammatic Sections across Collie- Stirling Trough 



Vertical Scale 8000 feet to an inch 



M^Toolbrunup. 3341^ 



Collie Coal Field 



_ lt Lookinq W.N.W ,_ 

 fault 3 Fault 



3SI 



s \ \ 



In addition to the evidence of the faults, the trend lines 

 of West Australia are indicated by : — 



(1) Prevalent strikes of folds in sedimentary rocks. 



(2) The trend of the metalliferous (especially auriferous) 



belts. 



(3) The direction of the foliation and schistose structure 



in the gneisses and schists. 



(4) The trend of the banded jaspers and hornstones. 



1 Permo-Carboniferous. a Older Palaeozoic. 



