PROTOZOIC ROCKS OF THE NORTH OF W.A. 
55 
limestone was. met with by Mr. Talbot on his traverse from 
Wiluna to Hall’s Creek along the Canning Stock Route. 
The southerly boundaries of these Ordovicians are 
unknown. Mr. Brown’s map of the Northern Territory 
and South Australia, published twelve or thirteen years ago, 
shows that the beds extend considerably to the east of the 
129th parallel. And Mr. Talbot's work done in connection 
with the Canning Stock Route fixes the S.W. boundary at 
approximately 22|° S. and 123 0 E. 
How far they extend in other directions is not known, 
though we may assume that they cover practically the 
whole area between the Stock Route and the South Aus- 
tralian border. To the north-west of the route they seemed 
to stretch for many miles. The auriferous belt of Hall’s 
Creek does not appear to extend further to the south-west 
than is shown on Ur. Jack’s map, for as far as is known to 
me, prospectors have failed to locate any metaliferous 
outcrops in that direction. And all accounts of traverses 
of the sandy desert point to the fact that the class of country 
remains unaltered right to the Ninety Mile Beach. 
At their south western extremity and in the vicinity of 
the Albert Edward Range, these undoubted Ordovician Beds 
are seen to rest unconformably against rocks which have 
previously been classed as Devonian. Wherever these older 
rocks are exposed they consist of the same indurated sedi- 
ments usually argillaceous or arenaceous, but at times in- 
cluding bands of limestone. 
They cover a large area in North Kimberley and are 
also well developed in the North West Division, where 
they have been mapped by the Government Geologist and 
Mr. H. P. Woodward. I feel convinced that in the Kimber- 
ley District, at any rate, these beds are much older than 
Devonian ; they underlie the series which I propose to name 
the Ordovician, and although not seen in actual contact with 
the Cambrian Limestones, must pass under them, too, for 
obvious reasons, for them I suggest the name of Pre Cam- 
brian. 
In the Albert Edward Range some fine sections are to 
be seen which show' the Archaean complex of the Hall’s 
Creek series, unconformably under these Pre-Cambrian, 
which in their turn have the horizontally bedded Ordovicians 
resting against their upturned edges. 
In the Kimberley district we therefore find that the 
true Carboniferous beds are confined to the western portion 
south west of a line joining the Oscar Ranges with the 
coast. 
In the other parts of the division a much older sequence 
is presented. The sediments there consist of : — 
