HORN KXPEOITION — PHYSICAL (iEOfiRAPlIY. 19 



tlici-cfon', .s('\(.'ii times as large as tlie (ireat liasiu ot" North America. It will 

 thus be I'eadily umU'rstdod that the lakes, which foi'iii the centres of the several 

 drainage basins, an; physical features of the greatest interest and importance, 

 yurrounding the area of internal drainage is a strip of country stretching iidand 

 fi-oni (he coa,st for varying distances, throughout which the rivers cany the surface 

 water to tiie ocean. 



Only two lais'es occur in the region consider(.^d in this paper, viz., Lakes Eyre 

 and Amadeus, each of which forms the centre of one of the divisions of the internal 

 basin. JJotli of these are fast }>assing into the state of dry basins. This is due in 

 the tirst place to the aridity of the climate thi'oughout the region occupietl Ijy 

 them, fidui which results an almost total absence of superlicial How of water into 

 the lakes, especially Lake Aiiiadeits ; and in the second ])lace it is due to the 

 accumulation in the lakes of sand, etc., transported tiiither by running wat(U- or 

 wind. These stat<'nients ;ipply in a special manner to Lake Amadeus, the aVisence 

 of surface water near its western extremity at any rate being specially noticed by 

 Mr. Tietkens. 



From the sandhills bordering the lake nt;ar Ciosse's Crossing, i.e., towards its 

 eastern extrennty, we could make out no water on its suiface. There the dry bed 

 of the lake \\as crosseil without trouble en raute to Ayers Rock and Mount (Jiga. 



( If these two lakes Eyi'e is the lai'ger and the more important, and will be 

 considered lirst. 



Lake Eyre. 



Lake Lyre recei\es the drainage from the McDonnell Ranges, and the ranges 

 lying innnediately to the south of them, together with the drainage from a great 

 part of west and soutii-west (.Queensland. Its basin includes those of all the rivi'rs 

 that drain into it, and having no outlet it is entirely encircleil by a line of water- 

 parting. The draiiiage throughout the basin is to the tS.E., >S., and S.W., Lake 

 Eyre itself being situated close to the southern Ijorder of the basin. 



The Lake Eyre Rasin occupies the eastern half of South Australia between 

 the northern ternjination of Flinders Range and the McLonnell Ranges, and 

 the greater portion of west and .south-west t^ueensland from the (heat Dividing 

 Range westwards. The rivers which drain this enormous area aie taken in order 

 from west to east, the Neale.s^ Macundxi, Finke, Todd, llale, Handover, Plenty, 

 Mulligan, Diauii'utina, and Cooper or Rarcoo. 



