150 president's address — SECTION c. 



Cambrian and the Cainozoics. It is possible tbat, during tliis enormous 

 interval of time, thick sediments may have been laid down within this 

 area, during one or more geological periods, and have been entirely 

 removed by denudation. Such would have been the fate of the Permo- 

 Carboniferous glacial beds, as well as the Jurassic fresh-water beds of 

 Leigh's Creek and the isolated upland fragments of the Lower Cainozoio 

 marine beds, had it not been for special circumstances of a local charac- 

 ter that favoured their preservation. Indeed, the survival of the 

 Permo-Carboniferous terranes would seem to imply the existence of 

 a Mesozoic, as well as a Cainozoic, protecting cover, to secure the 

 preservation of these feebly coherent rocks through the long interval 

 down to the present day ; but as to the age and nature of such lost 

 records, if they ever existed, we have no knowledge and it would be 

 useless to speculate. We know that the thick Cambrian sediments 

 have been subjected to enormous waste and worn down, in places, to 

 their lowest members and exposed the base-level of an older continent. 

 In this process of severe denudation some newer formations may have 

 been entirely removed. 



Throughout the Palaeozoic periods important highlands existed 

 further to the south than the present coastline, and the drainage was 

 directed to the north. This is seen in that the trend lines of glacial 

 dispersion, which prevailed both in Cambrian and Permo-Carboniferous 

 times, originated in higher latitudes than the present limits of the 

 continent, and travelled north. The cretaceous sea came as far south 

 as Hergott, and it seems probable that the northerly-directed drainage 

 was maintained until altered by the same earth movements which led 

 to the withdrawal of the cretaceous sea from Central Australia. 



A discovery of great importance has lately* been made on the south 

 coast of Western Australia, which proved that the cretaceous sea had 

 an existence in the neighbourhood of Eucla. A bore put down at 

 Madura, at the base of the Hampton Range, first penetrated ,the 

 " Eocene " limestone of the district, and then, at a depth of 903 feet, 

 entered a series of shales and dolomitic bands of rock that continued 

 to a depth of 2041 feet, but was not bottomed. Another bore, situated 

 further to the north, went through a similar section but reduced in 

 thickness ; the " Eocene " limestone in this bore had a thickness of 

 603 feet, and the underlying shales, a thickress of 667 feet, the latter 

 resting on bedrock. In the shales of this bore, fossils characteristic 

 of the cretaceous of Central Australia were found (Aucella hughen- 

 densis and Maccoyella corbiensis). Whether this part of the cretaceous 

 sea had any direct connexion with that of North and Central Australia 

 is now impossible to say. Such a connexion may have existed across 



• See Lecture on " Some Greological Considerations affecting tlie Artesian Water Supply 

 of Wesfcern Australia," delivered by Mr. A. Gibb Maitlaud, before the Western Australian Insti- 

 tnte of Engiaeere, 1912. 



