48 Transactions. 
fauna is so like that elsewhere in the Rolling Downs series that it appears 
preferable to consider the former as deposited not in a separate gulf, as 
Walkom indicates (1918), but as the extension of the sea into and beyond 
the northern depressed area wherein Jurassic sedimentation had taken 
place. There is also some doubt (expressed notably by Ward—private 
communication) as to whether this Cretaceous sea reached as far south 
as the bight where Cretaceous fossils have been found in strata concealed 
by overlying Lower Tertiary beds. Ward draws attention to the present 
absence of any connecting strata crossing the broad area of ancient 
gneisses and other crystalline rocks between these and the main mid- 
continental development. That such a connecting zone may have been 
present, and has now been very largely stripped off, laying bare its 
foundation, is suggested by the occurrence at Eucla, in beds beneath the 
Tertiary cover, of typically Rolling Downs genera such as Maccoyella 
corbiensis, Aucella hughendenensis, and Fissiluna, reported by Maitland 
(1919). This is indicated on the chart, which is a modification of that 
suggested by Walkom (1918). In this great mediterranean the fauna 
developed many endemic forms sharply distinct from those on the north- 
west coast of the continent, as wil be shown. We may here record 
parenthetically the recent discovery by Talbot and Clarke (1918) of 
glaciated boulders in these rocks in the south-east of Western Australia, 
thus confirming an earlier report of a similar discovery by H. Y. L. Brown 
(1905) in the northern parts of South Australia. Each of the authors 
considers the glaciation to be of late Cretaceous age, or possibly early 
Tertiary (see also David, 1907). : 
ollowing the Cenomanian period of greatest flooding, there seems 
to have been an almost complete withdrawal of the sea from central 
Australia, and a slight crust-flexing and erosion took place before the 
that in Upper Cretaceous times central Australia was mostly emergent, 
while the sea was transgressing on to the marginal regions of New Caledonia 
d 
occurrence of Cretaceous rocks in Western Australia is quite 
. 
different from the above. At Gingin is a small area of chalky limestone, 
are also species of Inoceramus and ammonites, h 
in the Rolling Downs beds (Etheridge, 1913). Chapman (19174) has 
recognized 134 species of foraminifera in this rock fifty-nine of which 
are restricted to the Cretaceous in other parts, chiefly Europe, and of 
these a fairly large number have hitherto been known only in the Gault 
(Albian) formations. He therefore concludes that the fauna is, on the 
whole, not Lower Cretaceous, but Albian-Cenomanian. It thus probably 
retreat of the sea from its central region. Twenty of the species recognized 
have also been recorded by Howchin (1893) from central Australia. 
Near Port Darwin Belemnites beds stated to be of “ Upper Cretaceous "' 
age occur їп " numerous pockets and patches mostly of slight area along 
