GEOLOGICAL RECONNAISSANCE OF THE STIRLING RANGES. 10^ 



of view of denudational forces, an aspect which will be 

 treated later. 



Transversely the Range is essentially a broad syncline. 

 On the south-eastern escarpment there is almost certainly 

 evidence of heavy faulting, and there is almost equally 

 strong probability of a similar fault on the northern border, 

 so that the area may be described as a trough-faulted 

 syncline. In at least one instance, namely west of Tool- 

 brunup, there is evidence of a fault line well within the 

 range, in the same general direction as the faults above 

 postulated. 



In the western section of the range the structures noted 

 from Mondurup to Ross Peak indicate an anticline rather 

 than a syncline. Transverse faults, or folds, or both, are 

 suggested by the structures of Yungermere and Magog 

 respectively. 



In several places the results of compression are clearly 

 defined, and similar phenomena may be inferred with some 

 certainty elsewhere. The overthrust faulting from south 

 to north, with formation of crush conglomerate, on 

 Warrungup, and the easterly directed overthrusts on 

 Talyuberlup are the most definite cases. 



Age of the Stirling Range Series. 

 When examined superficially and compared with geological 

 features in Eastern Australia, the dominance of horizontal 

 stratification and apparently insignificant metamorphism 

 strongly suggest that the beds are not very ancient, cer- 

 tainly not older than Palaeozoic. When, however, the area 

 is more closely studied it is found that very considerable 

 disturbances of stratification have occurred, including 

 overthrusting and formation of crush conglomerates, and 

 that the rocks are much more profoundly altered than one 

 would at first suppose. In fact, considering the general 



