109 



Lofty and Barker, composed of a resistant rock, usually 

 quartzite. In comparatively recent, probably at the close of 

 Pliocene, times this peneplain was elevated, by upthrust 

 chiefly, rather than by folding. < 4 > 



Stratigraphical proof of this uplift is afforded by the 

 presence of raised marine Eocene fossils < 5 ) on the hills behind 

 Encounter Bay, at the head of the Hindmarsh River, < 6 ) where 

 they occur at an altitude of 1,000 ft. 



Mr. Howchin has also noted the presence of steeply 

 dipping and overfolded Tertiary beds near Sellick's Hill.( 7 > 

 By this movement the drainage was much altered. Erosion 

 readily removed the soft glacial clays and sandstones from 

 the Inman, Hindmarsh, and Upper Finniss Valleys, and in 

 the first named exposed in places the hard glaciated Permo- 

 Carboniferous land-surface . < 8 > 



The uplift was not en bloc, but the area was broken up 

 into larger and small blocks which were differentially elevated, 

 tilted to> some extent, and possibly slightly flexed. This 

 makes fault scarps a frequent feature. ^ The small inset 

 model shows the series of fault-blocks that form the western 

 flanks of the range. They are roughly triangular in shape 

 and are tilted sloping to the south. They may be due to 

 differential elevation in the first instance or may have dropped 

 off the main peneplain, collapsing after their original uplift. 



A somewhat similar series of steps, though less well 

 marked, appears on the eastern flanks of the Range, as at 

 Palmer and the Bremer Range. It is possible that Mount 

 Lofty and perhaps the Forest Range are on a block raised 

 above the general level, of which German Town Hill would 

 be the eastern scarp. This feature is not shown on the 

 model, however, chiefly because it has not been sufficiently 

 studied by the writer. 



Backstairs Passage, the narrow strait that separates 

 Kangaroo Island from the mainland, may have originated in 

 one of two ways. There can be little doubt that the high flat 

 surface of the island is a continuation of the peneplain of the 



(4) Compare R. Tate, Trans. Roy. Soc, S.A., 1884-5, pp. 

 56-7 ; also E. C. Andrews, Geographical Unity of Eastern Aus- 

 tralia, Proc Roy. Soc, N.S.W., 1910', especially p. 440. 



(5)R. Tate, Proc. Roy. Soc, N.S.W., 1888, p. 242. 



t&)W. Howchin, Trans. Roy. Soc, S.A., 1898, p. 15-6; also 

 present volume ante pp. 55-6 and pi. x. (inset). 



(?) See present volume, ante, pp. 47-59. 



(5) W. Howchin, Report of the Australasian Association for the 

 Advancement of Science, 1907, p. 267: also Trans. Roy. Soc 

 S.A., 1910, p. 1 and p. 231. 



(9) W. Howchin, present volume, p. 53. 



