NOTE ON THE GREAT AUSTRALIAN ARTESIAN BASIN. 



433 



submit the Jurassic sandstones to a critical examination as to their 

 capabilities in this direction." 



Dr. du Toit is completely mistaken, as no such "admis- 

 sion" was ever made by me. 



The term Blythesdale Braystone was first adopted by 

 Dr. R. L. Jack, who described it (in 1895) as a very porous 

 marine sandstone forming the lowest bed of the Lower 

 Cretaceous Series (Rolling Downs Formation). But it has 

 recently been made clear that the lowest bed (A) of the 

 Lower Cretaceous Series has none of the characteristics 

 of a braystone, but is a Fontainebleau limestone, while the 

 uppermost bed (B) of the Jurassic Series is a freshwater, 

 and not a marine sandstone. 



LOWER CRETACEOUS. 

 Marine Series. 



JURASSIC. 



Fresh-water Series. 



WEST 



EAST. 



The question, therefore, arises as to which rock, A or B, 

 Dr. R. L. Jack intended to designate by the name "Blythes- 

 dale Braystone"? I have no doubt whatever that it was 

 B, because in the Geological Survey Office in Brisbane, in 

 the year 1896, I was shown some hand specimens of the 

 so-called Blythesdale Braystone, and they were similar in 

 litbological character to the rock forming the bed B. But, 



Bb— November 7, 1917. 



