116 
Rex T. Pkider. 
tnu* lat.erito dovoloiied in situ on llu‘ t'evrn^inous sandstones and not a | 
lateritite as su^'gested by Simi)son for the low-level lateiites g'enerally. j| 
(i) The high-level laterite varies in eharaetei- aecordin^^ to llie nature 
of Ihe underlyinu' Rre-(’ainbrian rocks. Jii one ])lace in tlie area when' it 
overli('s granitt' containing {juarlz veins it is crowded Avith larg(' <|uartz 
fragments. When develoi)ed over granitic rocks it genei'ally iias a ])iso!itie 
structure and is coni|»arative]y light-colourt*d but when over e])idiorite 
{as at the northern end of the high-level laterite outlier in the south-east 
coiner of tin' area) tlierc' is no pisolitic stnndure hut tlu' rock is somewhat 
cellular and appears to Ik' riclun* in iron, ih.ese iniii oxide i)atches being 
compact, tine-grained .and massive. .Ml the high-level laterites are under- 
lain by a higlily weatlu'red ( kaoIinis(*d ) /one which pass(‘s down into the 
nnweatliei'(‘d country rocks ns de.scrilied by Simpson (U)ll2). Analyses of 
tAvo high-lev(*l lateriti's aia' gi\en in Table I. cols. Ilf and I\'. Analysis 
!TJ is of a latf'i'itc developed over opidiovite from tlie Kidge Hill area. 
Analysis W piloted frtmi Si;ni>son p. 464) is from (fooseberry Hill 
which is sitnaU'd a|)]iroximately one mile south of the Kidge Hill area, ' 
but no details of the c.xaet loeality are available. Through the courtesy 
of the (lovertiment iliueralogist and Analyst 11. RoAvley) I have 
been able to e.xamine SinpisoiHs analysed syiecimen — it is a dense reddish- 
broAvn rock Avitli numerous iron-rich com-retions scattered uniformly 
throughout. The Kidge Hill sjiecimen ( Analysis HI) is a dense brownish 
coloured rock with occasional cavities pi'oducing a slightly cellular struc- 
ture but concretionary stimctures ar(' absent. (^Inunically the tAvo rocks 
dider in the loAver f'e/Al ratio of the (looseberry Hill rock. 
Tablt'] T. 
ANAl.YSES OF FERRUGINOUS SANDSTONE AND LATERITES FROM RIDGE HILL. 
:r. 
IT. 
HI. 
TV. 
SiO.,* 
m • 98 
44-87 
10-80 
6-41 
AU) 
8-17 
24-63 
22-58 
86-74 
Fe.,0, 
27-68 
14-82 
48-56 
89-80 
TiO., 
0-99 
1-25 
8-24 
1-98 
Mii() 
0-02 
0-01 
0-05 
0-06 
H.,Ot 
4-40 
14-61 
15-82 
14-98 
Others 
... 
0-51 
100-14 
100-19 
100-50 
100-48 
^Combined SiO., ... 
5-42 
8-18 
4-94 
1-97 
tLoss on ignition. 
r. Ferruginous sandstone (22798). three feet heloAv laterised surface 
rock in quarry 25 chains nortli of Kidge Hill Siding. AV.A. {Anal. 
H. T. f'ridei'.) 
11. LoAA’-level latente (2185!)) overlying ferruginous sandstone, from quarry 
25 chains north of Hidgt5 Hill siding, fV.A. {Anal. R. T. Pri<ler.) 
III. High-level laterite (22797) from northern end of outlier of the hii^h- 
level laterite, 45 chains south-east of Kidge Hill sifting, WrV. 
{Ami. K. T. Pridcr.) 
IV. High-level laterite. Gooseberry Hill, AV.A. (no further lo<-ality details- 
available), (Simpson, 1912. p.404.) 
