president's address. 555 



In the Mount Macdonaell Ranges the Archaean rocks attain an 

 altitude of from 3000 feet up to 4000 feet, and possibly 5000 feet, 

 at Mount WoodrofFe, in the Musgrave Ranges. 



Their thickness has nowhere been acourately measured in the 

 Australasian region, but, as I am verbally informed by Professor 

 Ralph Tate, it is very vast near Adelaide, perhaps as much as 

 50, COO feet. 



The marble at Ardrossan, the thickness of which is said to be 

 considerable (to judge from Mr. Otto Tepper's sections,* it appears 

 to be not less than 100 feet), is of special interest, the immense 

 unconformability between it [together with the conformable (?) 

 Parara limestones, containing abundant fragments of Archceocya- 

 thince, Olenellus Pritchardi^ and Salterella planoco7ivexa\ and the 

 underlying rocks proving the age of the latter to be undoubtedly 

 Archaean. The marble of the Macdonnell Ranges, the limestone 

 in the Archaean rocks of Tasmania, and the graphite associated 

 with the Archaean rocks of S. Australia aie very suggestive of 

 contemporaneous animal or plant life. 



The scales of graphite recorded by Captain Huttonf as occurring 

 in the mica schist of Duskey Sound, New Zealand, might also be 

 taken as evidence of probable contemporaneous life in Archaean 

 time, but, as has been shown, it is not yet certain that those schists 

 are truly Archaean. 



Tha^t the movements of the earth's crust, which laid the founda- 

 tions of the Australian Continent, commenced in Pre-Cambrian 

 time is conclusively proved by the vast amount of folding to 

 which the Archaean rocks at Ardrossan and in the Mount Mac- 

 donnell Ranges were subjected before the deposition of the earliest 

 Cambrian sediments. 



In Tasmania the crumpling of the crust took place between 

 E.N.E. and W.S.W. directions, so that the axes of the folds trend 

 N.N.W. and S.S.E. 



At St, Vincent's Gulf, near Adelaide, the folds run chiefly 

 N.E. and S.W., and N.N.E. and S.S. W., so as to meet, if produced, 



* Loc. cit. pi. II. between pp. 80 and 81. 

 t Loc. cit. p. 198. 



