54 



expanse. The basin of Lake Torrens exhibits the same- 

 peculiarities as that of Lake Ejre ; the margin of the former 

 lake is 111 feet above, whilst that of the other is 39 feet below 

 sea level. The river courses of the Lake Torrens basin are 

 short and rapid, the rainfall is a little more, and not unfre- 

 quently the creeks discharge their contents into the lake. 



With the features of the Lake Torrens basin I am familiar, 

 and will subm.it now the chief facts which induce me to the 

 opinion that the present lake is but a remnant of its former 

 self, and that the sandhills are of lacustrine origin. 



The plain of Lake Torrens is at its margin chiefly composed 

 of loams and gravels, shed from the adjacent slopes, or trans- 

 ported from the far distant Flinders Eange by the torrential 

 streams which debouch upon the plain ; other constituents of 

 the gravel are flints and agates quite foreign to the district. 

 Here I picked up a pebble of obsidian. Further out on the- 

 plain these drifts are concealed by low, more or less parallel, 

 sandhills separated from one another by loamy flats. The- 

 wide trumpet-shaped mouth of the valley of the Aroona Eiver 

 is occupied with breccia and conglomerate to 50 and 80 feet 

 above the level of the present stream course. 



The sandhills have a trend conformable with the edges of 

 the main body of the drift, which is by estimate at least 100' 

 feet above the level of the lake-waters. The sandhills are 

 covered with vegetation, and are quite stable. The sand is 

 coarse, sharp, and externally red coloured ; angular fragments- 

 of white quartz and dark-coloured quartzite up to five milli- 

 metres diameter may be gathered at the bases of the sandhills. 

 No fossils have been detected in the sandhills, but the loams 

 liave yielded remains of land vertebrates. 



3. Extinct Fauxa. — That the lake areas of Eyre, Torrens, 

 and Frome were once inhabited by terrestrial and fluviatile 

 animals now totally extinct or repelled is a well established 

 fact ; perhaps no other part of Australia has yielded suchi 

 abundant remains of Dip'otodon as that about Lake Eyre. 

 LTnfortunately the sequence of the beds yielding mammalian. 

 and other terrestrial remains is not known ; but whether they 

 be isochroaous or not — tableland sandstones, the deeper-seated 

 clays and gravels, the more superficial loams, or the sandhills 

 — they all indicate a lacustrine origin. Mr. Debneyf obtained 

 fossils from the escarpment of a table-hill, between the "War- 

 burton and the Cooper, on the east side of Lake Eyre, in the 

 midst of the sandhill country. They consist of the phalanges 

 and other bones of an emu-like bird, crocodilian scutes and 

 teeth, chelonian plates, and vertebrae of fish. Similar organic 



t Trans. Roy. Soc. S. Aust., vol IV., p. 140; 1881. 



