Journal of the Royal Society of Western Australia, 87(3), September 2004 
best developed flared slopes (Fig 4; 5 in Fig 1) are 
associated with this surface (Twidale 1962, 1968; Twidale 
& Bourne 1998a) as are large boulder fields which 
suggest prolonged and intense shallow subsurface 
weathering. Level II is readily correlated with the 
primary lateritic remnants of later Cretaceous age (Clarke 
1994; Twidale & Bourne 1998b) preserved on adjacent 
plateaux and high plains (Fig 5). The pisolitic ironstone 
(or ferricrete: see Twidale 1976, pp. 196-197) exposed in 
shallow pits close to the northwestern base of the 
inselberg is interpreted as a secondary or derived deposit 
lacking the kaolinised mottled and pallid zones of a 
laterite profile. It accumulated in a scarp-foot depression 
which formed as a result of weathering and lowering by 
runoff from the hill and which is typical of inselberg 
landscapes (Thorbecke 1927; Clayton 1956; Dumanowski 
124 
