Benson.—-Palaeozoic and Mesozoic Seas in Australasia. 15 
and has drawn from it such tentative inferences as seem justifiable at the 
present time, in the hope that such a summary may help to direct attention 
to this broad aspect of geology. The intmediate need is for careful revision 
of much of the palaeontological data, the more exact determination in the 
field of the horizon or stratigraphical range of the various fossils, and the 
palaeogeographic consideration of the lithology of the rocks which contain 
them. 
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Post- Cambrian Plutonic Rocks 
ШЇЇ Pre-Cambrian Schists- gneisses granites ambhibolifes etc. 
7777] “rystalline Schisis etc. of uncertain age 
ENSE Late Pre-Cambrian (‘Lower Cambr") Beds 
Jab 
"USiong in Pre 
Tug GEOLOGICAL HISTORY OF AUSTRALASIA. 
The foundation of the Australasian region is indicated as far as possible 
by map 1, which shows the areas of exposed definitely pre-Cambrian rocks, 
the probably late pre-Cambrian Nullagine rocks of Western. Australia and 
the possibly late pre-Cambrian or so-called * Lower Cambrian " of South 
