GLACIAL BOULDERS—CENTRAL AUSTRALIA. Lia 
Watt) being Supra-Cretaceous, and f. R. L. Jack and R. Etheridge, 
junior, Upper Cretaceous. The solution of this question as to the 
supposed identity of the friable sandstone of Yellow Cliff with that 
unconformably capped by Desert Sandstone at Crown Point is of 
considerable importance as bearing on the probable geological 
age of the glaciation. No glaciated pebbles were observed by 
Professor Spencer or Mr. Byrne in the friable sandstone either 
at Yellow Cliff or Crown Point, though some of its lower beds 
contain a number of well-rolled quartz “pebbles an inch or so in 
diameter, nor do they think that the glacial pebbles were derived 
from a disintegration of the friable sandstones. Tf, therefore, the 
friable sandstone which at Yellow Cliff immediately underlies 
the 2 feet to 3 feet bed (out of which the glacial pebbles have 
weathered) is identical with the steeply-dipping sandstone uncon- 
formably capped by desert sandstone at Crown Point, then the 
next formation below the glacial stratum at Yellow Cliff is 
Pre- PUL Uses (Tate and Watt), or Pre-Upper-Cretaceous 
(Jack and Etheridge), and judged by the degree of induration of 
the beds is not likely to be as old as Carbonifer ous, though it may 
possibly date back to the Permo-Carboniferous. The date of 
glaciation of the pebbles, according to this view, may be carried 
even as far back as the Permo- Carboniferous. If, however, the 
view be adopted, that the Desert Sandstone and the friable kaolin 
sandstone be conformable to one another, it is possible, though of 
course it by no means follows, that the age of the latter is 
Cretaceous. The fact, however, must be mentioned that in 
some parts of Australia, especially in the western district 
of New South Wales, as, for example, in the Gulgong and 
Home Rule District, near Mudgee, the Permo-Carboniferous 
strata are not only conformable with the Pliocene gold 
gravels, but also very like lithologically, so that the gold-miners 
have some difficulty at times in ascertaining in which “of the two 
formations their gold-workings are situated. In other parts, how- 
ever, of New South Wales, as in the Murrurundi district, there 
is a marked unconformity between the Tertiary and Permo-Car- 
boniferous rocks. 
Possibly analogous conditions may obtain in Central Australia, 
at Yellow Cliff and at Crown Point respectively, and the friable 
kaolin sandstone at one point may be discordant, and at another 
point concordant, with the Desert Sandstone. 
In South Australia, also, the strata which contain the glaciated 
boulders, fringing the coast, southerly and south east from Ade- 
laide, at Hallet’s Cove, Inman Valley, Port Victor, and Cape 
Jervis, are in places only slightly indurated, and there is no 
marked unconformability between them and the overlying marine 
Miocene beds, and yet there are reasonable grounds for believing g 
