28 
Hex T. Prider 
the alteration of these bedimentary rocks by a granitic magma, either the 
same or an earlier magma to that which provided the massive granites of 
Geological skctcli ina|) of the country between TTpper Swan and Mundijong 
and extending to the coast, showing localilies mentioned in the text. 
The present investigation was undertaken to determine if possible,, 
whether this ‘^granitisation” of the Cardup Series has actually taken place 
and to determine the relative age of the granitic gi.'eisses and the slaty sedi- 
ments of the Cardup Series. I am indebted to Mr. H. A. Ellis, Assistant 
Government Geologist of Western Australia, for suggesting that the possi- 
bility of granitisation of the Cardup sediments should be investigated. 
Tlie area examined in detail is situated on the Darling Scarp just south 
of the Xarrogiii Inn at Armadale, some 19 miles south-east fi'om Perth 
(fig. 1). It measures only about mile x % mile, but outcrops are fairly 
abundant; fresh examples of both the sedimentary and granitic rocks are 
obtainable in the two quarries; and most of the rock that have been 
