110 W. G. WOOLNOUGH. 



Pallinup. While this is a possible explanation, it seems 

 more probable that the lakes represent the expiring efforts 

 of a number of small creeks, heading in the Stirling Range, 

 to extend across the sand plain and reach the Kalgan or 

 the Pallinup. Originally they may have been successful, 

 but as the climate has become progressively drier, their 

 waters have failed to extend beyond the limits of the foot- 

 hills. This latter explanation is very strongly suggested 

 by the character of the gully crossing the old road south 

 of Sandalwood Station, which contains the quite consider- 

 able creek rising on the northern side of Ellen Peak. 



Earth Movement. 

 While the sketch of the physiography may explain some 

 of the later earth movements of the region, the complete 

 history of these movements is undoubtedly highly com- 

 plicated. It is obvious from the structure of the range 

 that it must be regarded as a well defined narrow sen- 

 kungsfeld bounded on the north and south by faults, and 

 as such it is indicated in the handbook prepared for the 

 Australasian Meeting of the British Association for the 

 Advancement of Science in 1914. The preservation of the 

 sedimentary series in such a narrow zone could have been 

 accomplished in no other way. 



The present altitude of the sedimentary series above the 

 plain is, however, more difficult to account for. Differential 

 erosion seems quite inadequate as an explanation. The 

 alternation of brittle, highly-jointed quartzites, and of 

 relatively soft slaty beds in almost horizontal layers yields 

 a structure which is almost ideally weak. It seems incon- 

 ceivable that such a structure could have withstood the 

 agents of denudation so much better than the massive 

 granites and gneisses, ribbed with greenstones, which form 

 the plains, as to have produced mountains over 2000 feet 

 high by simple differential erosion. The presence of the 



