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W. G. WOOLNOUGH. 



bears south 37 degrees east, so that the structures do not 

 conform at all closely to the mountain axis, and, in some 

 cases, cut almost perpendicularly across it. In a strongly 

 wedge-shaped foot-hill to the south-south-west of the 

 trigonometrical station, a precipitous scarp to the north 

 and a rather steep dip slope to the south indicate that the 

 southerly dip persists beyond the limits of the main ridge. 

 The continuation of the same structure can be seen in a 

 high peak to the south-east of Mondurup. In Ross Peak 

 the summit rocks, which are beautifully ripple marked, dip 

 north 5° west at 12°, which structure is reflected in the 

 precipitous southern face and gently sloping northern side 

 of the peak. As seen from Ross Peak, the rocks in Peak 

 Donelly appear to have very much the same inclination v 

 but Peak Donelly is by no means a rocky summit. At the 

 Slate Quarry the cleaved slates dip north 49° west at 17°. 

 At a point so close to the intrusive contact, however, it is 

 quite probable that the dip has suffered considerable local 

 variation. 



Summary of Structural Features. 

 It is obvious that the data obtained concerning dips, etc.,. 

 are far too scattered and scanty to determine in any detail 

 the structure of the Stirling Ranges. Several important 

 features are nevertheless outstanding. In the first place 

 the strong predominance of nearly horizontal stratification 

 is most remarkable. I have noted the most important 

 departures from horizontality actually observed in my 

 journey, and their recapitulation above may lead to an 

 erroneous idea as to the amount of contortion present. 

 Where no statements are made, it may be assumed that 

 the beds are essentially level. Such a mass of level bedded 

 sediments, consisting of alternate layers of hard, jointed 

 quartzites, and of relatively soft slates and phyllites, con- 

 stitutes an almost ideally iveak structure from the point 



