lxvii. 



tire powers of other areas diminished by the gradual dessication 

 going on. In this way the animals would be crowded on 

 limited areas, and a struggle for existence would ensue, in 

 which the less adapted and less easily modifiable would succumb. 

 Of these the larger animals would probably be the first victims, 

 because of their slow breeding powers and of insufficiency of 

 food within easy reach. The clumsy Diprotodon would soon 

 be worsted in the struggle, while the fleeter Kangaroos could 

 continue to hold their own for a longer period ; and the extinc- 

 tion of the Thylacoleos would be involved in that of its prey. 



Comparing the climatic conditions of the Pleocine Period — 

 distant, but geologically recent, with those of the Present 

 Period — we cannot doubt that a great change has come over 

 the surface of South Australia in the decreased amount of 

 water in the lakes or running in the rivers, in the increase of 

 its mean annual temperature, and in the depauperization of its 

 mammalian and avian fauna. Historical evidence affords no 

 data, and exact observations with the raingauge cannot 

 possibly have extended over a sufficient length of time to enable 

 us to decide whether this change has been continued to our 

 time. What little evidence can be adduced from geological 

 observations is to the effect that the tide of dessication has 

 turned, rather than to its continuance. The evidence to which 

 I allude is that of the recent elevation of land, by which process 

 our hill-tops are lifted into higher and colder strata of the 

 atmosphere, and aqueous precipitation is increased. That these 

 changes have occupied a vast interval of time is proved by the 

 amount of denudation our " Drift" has undergone, as exempli- 

 fied by the truncation of the Adelaide and "Willunga Plains. 

 In the case of the latter the Drift forms seacliffs rising to an 

 elevation of 350 feet, whilst its western boundary has been 

 totally removed. 



Pleistocene. 



The Eev. J. E. Woods describes the coast at Guichen Bay as 

 consisting of rough craggy rocks of coarse-grained sandstone, 

 " which, though not rising very high, are bold and abrupt, 

 sometimes presenting a perpendicular face to the heavy surf 

 which beats upon that coast." He recognises the false bedding, 

 notes the absence of fossils, and concludes " that the deposit 

 was from ocean current, but also that it was a considerable 

 distance from any land." He further remarks that it is found 

 more or less all round the coast of the colony of South Aus- 

 tralia, and perhaps it extends all along parts of the Australian 

 Bight. Personal examination of much of the whole coastline 

 between Cape Northumberland and Eucla confirms the state- 

 ment of Mr. Woods. In my paper on the country around the 

 Head of the Bight I have described this formation somewhat in 



