xlii. 



but more prominently in the conspicuous hills termed the 

 Hummocks at the Head of St. Vincent's Gulf, thence it follows 

 a curvilinear line with a general northerly direction to round 

 the head of Lake Torrens. The east coast of Spencer's Gulf 

 and Lake Torrens has the same general direction as this chain, 

 and to which it is in close proximity ; and also because of the 

 small annual rainfall, about 12 inches, though the elevation of 

 the range is higher than that of the Adelaide chain, the rivers 

 are all short, and for the most part do not reach the sea or 

 Lake Torrens. The highest points in this range are among the 

 highest in South Australia. They are — the Bluff, 2,404 ; 

 Mount Remarkable and Mount Brown, about 3,000 feet. 



The third elevated region is that of Eyre's Peninsula, which 

 does not seem to present any well-defined system. However, 

 the G-awler Ranges, on its north, are represented on our maps 

 as having an east and west strike ; and the high grounds about 

 Port Lincoln seem to have a north and south trend ; but to the 

 westward, certainly as far as Streaky Bay, the generally 

 undulating country is dotted over by isolated peaks, or short 

 razor-backed ridges showing no uniformity as to direction. 



All these elevated regions are constituted of the fundamental 

 rocks and their associated granites. 



The Adelaide chain is bounded on its western side by the 

 vast and fertile plain of Adelaide, which extends from Marino . 

 on the south, and sweeps round the head of St. Yincent's Gulf 

 on the north. ISTo inconsiderable portion has been removed by 

 the action of the sea, as it is abruptly terminated on the shores 

 of Holdfast Bay and at Ardrossan on either side of the Gulf. 

 The period of its formation is comparatively recent. Plains of 

 a like character are interspersed in longitudinal bands among 

 the parallel ridges of the Flinders Range and northern 

 extension of the Adelaide chain, though not one is equal in 

 magnitude to the Adelaide Plain. The two southern spurs of 

 the Adelaide chain enclose undulating plains, in part partaking 

 of the character of the Adelaide Plain, but mainly constituted 

 of rocks of much older, though of Tertiary date ; the northern 

 one is the "Willunga Plain, the southern is the Myponga Plat. 



On the eastern side of the Adelaide chain there stretches far 

 and wide the Plain of the South-East, towards the western 

 boundary of which flows the Lower Murray. The dimensions 

 of this plain are about 290 miles from north to south and an 

 average of 100 miles from east to west. The general level, 

 which is broken by low sandy ridges, does not exceed 200 feet. 

 The rocks composing it are of the same age as those composing 

 the AVillunga Plain and the lower tracts of Torke's Peninsula. 

 The prevailing uniformity of scenery is relieved in two limited 

 areas by isolated conical hills of granitic and of volcanic 



