118 
C’l-iARKE. — Natural Itcgions in Jl'cstcrn Australia. 
B. It may again bo divided into -major geological -regions. 
Those may ho exported to offeet a sub-division of the niajov 
])liysicnl regions, but to hannoiiize l)voadly vitli thos(> 
])liysieal regions. 
C. Climatic considerations, chiefly the amount and season of 
I'ainfall, will be found to necessitate further division of the areas 
arrived at by A. and B. 
By this stage we should have arrived at a classification into 
natural regions and our result should l)e in harmony with the dis- 
tribution of distinctive ])laiit associations. 
A. In the liroadest way this Btat(> can only be divided into two 
])hyslcal regions (Jutson, 1914, p, 19): (1) A low lying 
narrow stri]) running almost continuously along the coast 
from near Alliany to Broome. (2) A tnblelaml occipiying 
the whole interior of the Btate. 
B. ecologically Westei-n Australia may be divided broadly 
into : — 
(1) Western coastal stri]) of C’arbonifcrous or later age. 
{'2) 8outh-<'eutral Pre-Cdimbrian (chiefly Archaeozoic) 
shield — mineral bearing, cs])ecially in its eastern jiart. 
(d) South-eastern area (Cretaceous and later), which may be 
sub-divided into a norihern ]mrt, in which the rocks 
are mainly sandy, and a southern, in which they are 
calcareous. 
(4) Eastern Pre-Cambrian area. 
(.1) North-western Pre-Camliriaii area, ])redominantly Pro- 
terozoic, which is furth'cr divisilile into an eastern sec- 
tion, devoid so fai- as known of mineral dejiosits of 
economic value, and a western, containing ])atches of 
earlier Pre-(^‘lmbriall which carry minerals of value. 
(()) West Kimberley — ])redominantly Proterozoic or lower 
Cambrian. 
( 7 ) East Kiml)erley — Cambrian-Carboniferous with very 
large development of basalt. 
( 8 ) Area between (5) and (6) — Cambrian-Carboniferous 
(predominantly Carboniferous), but with minor devel- 
o])inent of Mesozoic and Cainozoic rocks, 
("• Cdimatic (rainfall) considerations, together with vegetational 
characteristics lead to further sub-divisions, which need not 
be particularised since they are shown summarily in the 
following tabular arrangement: — 
