9 
effects, these great intrusive granite masses, constitute a great 
significant and outstanding feature of the Western Australian 
goldfields geology. 
Owing to the physiographic features of the Central Plateau, 
erosion has not yet penetrated to any depth, hence it cannot be 
said that the anatomy of these masses has yet been thoronghlv 
understood. 
'I'hese granites are traversed by many large ice-like quart7 
reefs (Fig. KM which can be traced across country for miles; the 
mode of occurrence, etc., of these large quartz masses point to their 
being of igneous origin, representing the final product of the differ- 
entiation of a granite magma — its ultra-acid portion. 
