282 
BitKNDAN V. Thomson. 
(8) Fornialion of ]iost-rardiip (juart/ veins and the introduetion 
of ])arytic solutions. Both of these are the end-phases of the (‘pidiorites. 
Fnd of the Bre-(,^ainbvian. 
(0) Deposition of sedinnoits \V(‘st of llie area, leading to further 
dowinvarjjing whieh may have pi'odnced strain etfeets in tin* (puirt/ veins 
in tlu‘ slates, 
(Id) Continued erosion leadin^^ to i>eneplanation and laterite for- 
mation {Wo(tlnon^h, 1018, p. 385). 
(11) Uplift of the penejdain in late Mioeene times (Jiitson, 1034, 
])a”:c 205). and pi'ohable formation of the Darlinj^f Fault. 
(12) Further er<tsion, producino- tin* ])r('sent topography. 
VII. ACKNOWLFDtJMENTS. 
The author thanks the olTieers of the Lands and Survey Department 
for inakin" available tlie compilation data for the map. To Professor 
K. de C. ('Iark(‘ and Dr. R. 'V. Prider he is de(‘ply imh'bted foi* Ilnur ready 
help and advice durinj? the progress of the Avork. He is again very 
grateful to Dr. Prider and to Mr. C. E. S. Davis for valuable assistance 
during the revision of the text and for their collaboration in com})aring 
the three areas. 
VI IT. LIST OF K’EFEKKNrEB. 
Ailing, U. I.., 1923: ‘‘The. ATineralogy of the TVldspars. Part IT.'^ Jour. Geol.r 
Vol. XXXI., ]>p. 283-305, and pp. 353-375. 
I'larke, K. de and Williains, F. A., 192(i: ^‘Tlie (Jcology and Physiograi)liy 
of Parts of tlie Darling Range near l*erih.'^ Jo^ir. *S'oc. JV.A.j Vol XIT., 
j)p. 101 17S. 
Clarke, !'k do 1930: *^Tlie Pro-Cainbrian Snccession in some parts of Western 
Auslralia.'^ lirpf. Anst. and N.Z. Asmoc, Adv. Sri., 1930, pp. 155-192. 
(.'larke, F. de C., 193S: “Middle and West Australia.” HrgH>n<ile Otologic der 
F.rd<‘, Leipzig, ])|). 1-58. 
Cole, W. F., and Cloe, C. S., 1910: “The tieoiogy and Physiography of the 
Malknp Area.” Jour. Soc. II’.A., Vol. XXVT., pp. 139-171. 
Coulson, A. L., 1933: “Barytes in the ceded districts of the ATadras Presidency, 
with notes (ui its occurrence in other parts of India. “ Afe7n. Geol. S'urv. 
Tnd. Vol. LXIV., Pt. T., 1933, ]>. 114. 
Fsson, A. C. I)., 1922: “The Basic, Rocks of the Wongong Dam-Site.” CcoL 
Snrv. if\A. A/ru. h’cporl, 1922. 
Fsson, A. (i. 1)., 1920: “Tlie Silver-Tjead Dei)Osits at Alnndijong. Gcol, Surv. 
fl\A. Amt. Hcporl, 1920, ]»p. 4-9. 
Forman, F. (»., 1937: “A <5)nt ribntion to our Knowledge of the Pre-Cambrian 
Siuu'cssion in some Parts of Western Australia.” Jour. Fog. *Sec., IV. A. ^ 
Vnl. XXUl, p. xxiv. 
Ilonman, i'. S., Iitl2: “ TIte I'ixU'usion of the Kelms('ott Clay Deposit.” Geol. 
Siirv. iV.A. Gull. Xo. 48, p. 03. 
.tutson, .1. T., 1934: “The Ph vsiograjiliy ( ( ieoniorphologv) of Western Aus- 
tralia.” Geol. Surr. IV.A. Gull. 95. 
Laurence, It. A., 1939: “The Origin of th(‘ Sweetwater, Tennessee, Barite 
De])osits.” Ecou. Geol., Vol. XXXIV., pj). 190-200. 
Miles, K. R., 1938: “The Ceologv and Physiogra])hv of the Lower Cluttering 
Area/’ Jour. Fog. Sor. IV.A.', Vol. XX’lV, pp, 13-41. 
