550 president's address. 



poraneous or subsequent. These rocks are perhaps on the same 

 horizon as the Archseans of the Macdonnell Ranges about to be 

 described. 



(3) In the Macdonnell Ranges on the upper part of the Finke 

 River micaceous and hornbJende schists, dolomite and crystalline 

 limestone, and gneissic and granitic rocks have been provisionally 

 referred by Mr. Brown* to Archaean time, on the ground that 

 they are strongly unconformable to the overlying formation, and 

 the latter is in turn capped unconformably by a series of rocks, 

 the age of which has lately been proved to be Lower Silurian. 



These Archaean rocks were strongly folded along E. and W. 

 axes previous to the deposition of the overlying Cambrian rocks. 

 No conglomerates nor ripple-marks are recorded in the Cambrian 

 rocks, so there is no absolute proof that the Macdonnell Ranges 

 were a land surface in Pre-Cambrian time. It is certain, however, 

 that as proved by the immense beds of altered sandstone in the 

 neighbouring Cambrian rocks that land could not have been very 

 far distant, or, at any rate, if there was no land, the ocean there 

 must have been very shallow. 



(4) In West Australia, Mr. H. P. Woodward,! the Government 

 Geologist, has identified certain rocks as Archaean in the Kim- 

 berley District, as he considers them older than the Lower 

 Cambrian of that locality, characterised by Salterella and Olenellus. 



These rocks are of a schistose and gneissic character, and extend 

 from near the Denham River to Mount Dockrell, forming the 

 Mueller Range, a little further west, and striking in a N.W. 

 direction through the King Leopold Range to King's Sound. 



• South Australia. Report of Geological Examination of the country in 

 the neighbourhood of Alice Springs, by H. Y. L. Brown. By authority. 

 Adelaide, 1890. 



And also — Further Geological Examination of Leigh's Creek and Hergott 

 Districts, and General Geology on the Finke River, by H. Y. L. Brown. 

 By authority. Adelaide, 1892. 



t Report on the Goldfields of the Kimberley District by H. P. Woodward. 

 By authority. Perth, 1891. p. 10. 



