president's addrkss.— section c. 175 



(8) Finally, the whole face of nature became changed, the rank 

 vegetation that could not survive such uncongenial conditions was 

 wiped out and a new flora, suited to drier conditions, took its place. 

 With the passing away of the freshwater streams and succulent vege- 

 tation there went also a whole fauna that was dependent on such 

 bountiful supplies of nature, and were ill-fitted to face the hardships 

 of desert fare. 



Some of the old lake areas, such as Callabonna, for example, tell 

 a pitiful tale of the last struggles for existence among the larger her- 

 bivores of that transition period. Lake Callabonna, and other similar 

 sheets of water, were in the line of the flood waters that came down from 

 the north-east, and we may suppose that the waters along such a line 

 of drainage maintained a freshness in a higher degree, and down to a 

 later date, than the lakes of Central Australia that had a more isolated 

 position. To these rapidly decreasing freshwater holes the diproto- 

 dons, the gigantic kangaroos, and the great struthious birds (Genyornis), 

 with many others, came to quench their thirst. Hundreds of them 

 became bogged in the treacherous slime of the shallowing waters, 

 which formed the death-traps and the charnel-houses of races fighting 

 against destiny^ — the forces of destruction conquered and buried the 

 last of the Kadimakara. 



CONCLUSION. 

 In the light of certain facts that have recent!}' come under obser- 

 vation, we are able to speak with some confidence on subjects that have 

 hitherto been matters of conjecture only. The more important of 

 these, having relation to the physiographical evolution of South Aus- 

 tralia, are — 



1. The comparatively recent age of the Mount Lofty Ranges 

 and other uj)lands of South Australia. It was until 

 lately believed that these mountain ranges were of 

 very high antiquity, dating from the time when the Cam- 

 brian rocks were forced into stupendous folds and over- 

 thrusts by tectonic forces, and that the present uplands 

 are the worn-down remnants of very lofty and very 

 ancient mountains. That such effects were produced 

 at some period in the geological history of South Aus- 

 tralia, resulting in the formation of great mountains in 

 Post-Cambrian times, there can be no doubt ; but that 

 period of mountain-building has no relation to the 

 existing highlands of the country. Those old tectonic 

 mountains had become reduced to base-level long before 

 the present physiographical relief of South Australia 



