INAUGURAL ADDRESS. 4S 



and that it is by no means improbable that the Tertiary sea divided 

 West Australia from the eastern provinces," and again that " the 

 vast central area of Australia was a sea having open water to 

 the north, &c." 



Wallace* appropriates the idea that, " during the Cretaceous 

 period, and throughout a considerable portion of the Tertiary 

 epoch," Australia was divided into two principal insular masses, 

 an eastern and a south-western, a suggestion which, as already- 

 indicated, originated with Sturt thirty-five years before, and was 

 later adopted and supplemented by Jukes. 



From independent observations I had arrived in 1879f at much 

 the same conclusions as Sturt, though from different premises. At 

 that time I was not aware of his labors in this particular direction 

 and now make this tardy acknowledgment of Sturt' s instinctive 

 grasp of the nature and origin of the Lake Eyre basin. At the 

 date mentioned I sought to connect the relative high humidity 

 which prevailed in Central Australia, as indicated by the prevalence 

 of Diprotodon remains, with the glacial conditions which prevailed 

 farther south. Later :[, largely as the result of personal knowledge, 

 I endeavored to show that a vastly increased rainfall over what is 

 now the arid region of Australia during the Diprotodon Period is 

 demanded by the extinct rivers, circumscribed lacustrine basins 

 marked by their coincident sandbeaches, and the remains of large 

 herbivores, whilst the lacustrine origin of the low level deposits is 

 indicated by the presence of crocodiles, turtles, and fish. The 

 subter-structure of this vast lacustrine region, formed by the union 

 of Lake Eyre and the smaller lakes to the east and south-east of 

 it, is Lower Cretaceovis, whilst its extent is limited by the so-called 

 "desert sandstone," which almost entirely surrounds it. The last 

 occupation of this region by a sea was during Lower Cretaceous 

 times, and not, as has been currently held, during some parts of the 

 Tertiary epoch. Indeed this lacustrine area in still vaster propor- 

 tions existed during the accumulation of the Desert Sandstone; at 

 least that part of the formation surrounding Lake Eyre must, from 

 the land vegetation entombed in it, be regarded as of such an origin. 

 Consequently I have elsewhere§ expressed the opinion that the 

 isolation of West from p]ast Australia, which existed while Central 

 Australia was a marine area, was continued into late Tertiary times. 

 not by geological, but by climatic conditions — by conversion of 



♦Island Life, p. 465, 1880. + Trans. Roy. Soc. S. Aust., vol. 2, pp. Ixi.-lxvii. 



t Trans. Ro}'. Soc S. Aust.. vol. viii., p. 49, et seq. 

 5.\ust. Assoc. Adv. Sc, vol. I., p. 312, et seq.,l88lj. 



