86 
lected by Mr. Tietkens, was inclined to consider Mount Conner 
younger than the other two members."^ 
Desert Sandstone. 
The term Desert Sandstone, which was originally used by 
Daintree for a highly siliceoas deposit that is often found 
overlying the fossiliferous Cretaceous of Australia, is, to a cer- 
tain extent, misleading, as the formation is only to a limited 
extent a true sandstone. Mr. H. Y. L. Brown employed the 
term Super-Cretaceous, and later Professor Tate and Mr, Watt 
Supra-Cretaceous, for the same formation. Messrs. Jack and 
Etheridge regard the desert sandstone as Upper Cretaceous. 
No conclusive evidence concerning the exact relationship 
was found, but I observed that the desert sandstone in many 
places, particularly at Indulkana, unconformably overlies 
intruded primary schists. This fact, if the formation is to be 
correlated with the cretaceous, would demand, as Professor 
Tate suggested, that the desert sandstone overlaps the latter 
Beds of this formation occur along the track from 
Oodnadatta westward to Indulkana. Such irigonometrically- 
surveyed heights as Mount Mystery, Mount Alberga, and De 
Rose Hill are prominent members of the series. From in- 
dulkana, the north-western limit of the formation in South 
Australia runs east of north in a direction west of Crown 
Point ; beyond this line the primary and intrusive rocks or 
the Musgrave, Mann, Tomkinson, and Everard Ranges, :;o 
doubt, were high land surfaces during the deposition of 5,he 
desert sandstone formation. Slight surface exposures only 
of the so-called sandstone were observed, immediately i-oriili 
of the Mann Ranges at Hector's Pass, in the form of a low 
bank of rather dscomposed, friable, silicified quartzite .and 
white, semi-opaline quartz a mile or two east of the pass. A 
similar semi-opaline rock was found a few miles south-east 
of Giles West Camp (Musgrave Ranges), and south of Ayers 
Ranges, in the Northern Territory. Indications of the for- 
mation exist, as rock fragments, strewn on the surface, north 
of the Mann Ranges. 
To the south, the whole of the elevated country lying 
between Oodnadatta and Lake Torrens that was traversed by 
the Exj^edition, consists of desert sandstone, with the excep- 
tion of comparatively few exposures of palaeozoic rocks, as in 
the neighbourhood of Mount Woods and at the head of Lake 
Torrens, 
The formation, as a whole, occurs either as isolated 
table-topped hills or as groups and ranges of the same. The 
* W. H. Tietkens: Journ. Centr, Austr. Expl. Exped. : Sec- 
tion bv H. Y. L. Brown. 
