president's address. 19 



Marine Plains of Curtis Island are considered by residents to 

 show a recent elevation.* 



Thoiigh the Carpenter Deep extends downwards to 2450 

 fathoms, it is shown by the temperature soundings of the 

 "Challenger" to be an enclosed basin of the Mediterranean 

 type up to the level of 1300 fathoms. A ridge, yet unsur- 

 veyed, evidently runs eastwards from the Great Barrier 

 Reef, parting the Thomson from the Carpenter Deep. It is 

 here proposed to name this the Capricorn Ridge. 



Eastern Australia is regarded by Mr. E. C. Andrews! as 

 a "geographical unity'' whose salient feature is a simple 

 convexly curved coast. From this he deduced that move- 

 ments would proceed from the land seawards. That unity 

 appears to me to be divisible into halves, one of which is 

 dominated by the Carpenter ; the other by the Thomson 

 Deep ; the former being the younger and more active depres- 

 sion. So I should interpret the convex curve of Andrews as 

 composed of two straight or conravr lines, according to the 

 depth of the submarine contour level selected. One of these 

 is inter-tropical, the other extra-tropical and each again con- 

 sists of series of smaller concavities. 



The longest rivers of Eastern Australia, the Fitzroy and 

 the Burdekin, occur opposite the broadest expanse of the 

 shelf. I suggest that the bread th of the shelf has presierved 

 the Jenffth of these rivers and presents it as a submarine but- 

 tress maintaining a buttressed area. (Fig. 3.) Probably 

 this part of the shelf continues to exist rather from the 

 avoidance than from the resistance of j^ressure. Festoons 

 of islands and a dissected coast indicate that subsidence has 

 occurred. So that the escape from pressure, even within this 

 broadest shelf has been partial, not complete. The outline of 

 the shelf and the islands that it carries shew that it cannot 



* AiuJrews, These Proceedings, xxvii. , 1902, p. 153. 

 t Andrews, Proc. Roy. Soc. N. S. Wales, xliv., 1910 (1911), p. 462. 



