Joi K. Ho^■. 8oc. Western Avstkalia, \'ol. XII, Xo. 18. ini 
The Geology anid Physiography of Parts of the Darling Range 
near Perth, by E. de C. Clarke, M.A., Lecturi'r in Geology, Uni- 
versitv of Western Australia, and F. A. Williams, 13. Sc. 
{l^ead July 192(). J^uhlished August 1?>, 1926.) 
Contents. 
I . — Introduetioii 
II. — !diysi()gru])liy — 
A (Tcueral 
13 Physiography of the Darlington Area . . . . 
1, Helena River 
2. Tributaries 
!). IntiueiH'e of geology on stream directions 
4. High level terraces of Helena Valley . . 
Page. 
l .()2 
KH 
165 
l(i') 
165 
166 
167 
III. — Geology — 
A General 
13 Acid Rocks 
1. Granite 
2. Piiie-g]-aine<l biotitic segregations 
Acid and Ultra-acid intrusions 
4. Magmatic History 
C Basic Rocks 
1. General held-occiirrence and petrology 
2. Relations to other rocks 
;3. Inter-relationships <if the basic rocks 
D C^uartz Reefs in Rhea]- zones 
1. Rhear-zones without secondary (piartz 
2. Rhear-zones with partial replacement of slieared 
rock lyv quartz 
E Later Rocks 
1. Laterite 
2. Alluvium 
;3, Talus 
IV. — List of References 
167 
167 
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