280 
Bkendan P. Thomson. 
The ^Toothill zone’' (p. 266), which is partly underlain by the Cardiip 
Series, can be attributed to the effect of differential ei’osion between the sedi- 
ments and the granite gneiss. 
C. Comparison of the Wongonu-Cardap, Armadale and Gosnchs Areas." 
All three areas are situated on the Darling Scarp, on an igneous meta- 
morphic complex, flanked on the west by the Cardup sedimentary series which 
strikes almost due north and dips steei)ly to the Avest. 
Fig. 1. 
There are as yet insuflicient data to give a complete structural pi{‘ture of 
the igneous-metainorphic complex. The knoA\m facts from the three areas 
examined (which are illustrated in 6g\ 1) art': — 
(1) The. predominant I'ock in the areas examined is a hybridised gneiss 
which is best developed in the Wongong-Cardup and Ai’inadale areas. In 
the Wongong-Cardu]) area the gneiss is consitlerably folded and the strike 
varies from N.W. to N.N.F. while in the Armadale area the general strike 
is almost due north. At Gosnells the granitic rocks are generally nia.ssive 
without any gneis.sie structures. Post-gneiss massive granites occur at both 
Armadale and Wongong-Cardup Avhere they form only a minor ])art of the 
complex — these granitic rocks (aplogranites) may possibly be offshoots from 
the main Darling Range massive granite which lies to the north of Gosnells. 
*This section was written in collaboration with Dr. R. T. Prider and Mr. C. E. S 
Davis. 
