ARTESIAN WATER IN WESTERN QUEENSLAND. 
335 
is itself succeeded by bedded basaltic lavas). Nothing is more certain 
than that no member of the Lower Cretaceous formation appears on 
the north-eastern side of the Desert Sandstone and basalt tableland, 
which forms the divide between the waters draining southward into the 
Great Australian Bight and those draining eastward into the Pacific. 
In some places, however, as at the head of the Warrego on the Bight 
side, and at the head of the Nogoa on the Pacific side of the almost 
imperceptible watershed, the denudation of the Desert Sandstone 
(which apparently has a very uneven bottom) exposes larger or 
smaller areas of the Blythesdale Braystone, 
On the divide between the head waters of the Warrego and 
Barcoo the Desert Sandstone remains as a tongue which covers the 
whole of the outcrop of the Blythesdale braystones, and on its western 
margin directly overlies the shaly members of the Lower Cretaceous 
formation. A glimpse of the braystones is seen at the head of 
Birkhead Creek, covered to the north and east by the Desert Sand- 
stone, and succeeded to the south-west by the shaly beds of the 
Bolling Downs. 
Further north, on the head waters of the Barcoo and the Thom- 
son, the Desert Sandstone extends as a comparatively narrow tongue 
as far west as Barcaldine. Prom beneath this formation the Blythes- 
dale braystones emerge at a point on the heads of Aramac Creek, 
about 85 miles north-west of Jericho, and have been followed north- 
ward through nearly 2 degrees of latitude, until it is again covered 
by the Desert Sandstone, in the vicinity of Corinda Station. The 
western edge of the Desert Sandstone rests directly on the Lower 
Cretaceous shales from this point as far as Huglienden, and the 
Desert Sandstone forms an unbroken escarpment of about 80 miles in 
length, and entirely conceals the Blythesdale braystones from view. 
The convenient phrase, “ the exigencies of travel,” must again be 
employed to explain the difficulty of running with accuracy two lines 
which may be 20 or 30 miles apart. Granting that the two men 
employed can do a good deal on horseback, they must keep in touch 
with the main camp, for a survey party as well as an army “ marches 
on its belly,” according to the saying of Frederic the Great, and on a 
long journey horseflesh must be husbanded with care. For this reason 
attention was, north of the Warrego, mainly directed to the delimita- 
tion of the outer or eastern boundary of the Lower Cretaceous forma- 
tion. The presence of the Blythesdale braystones, however, has been 
ascertained, as has already been mentioned, at different points as far 
north as Corinda Creek, a tributary of Torrens Creek, operations 
having had to be suspended at Hughenden. 
In the region where an attempt has been made to map the whole 
area covered by the outcrop of the Blythesdale braystones — viz., from 
near Chadford, on a head of Yeulba Creek, to the Warrego — the out- 
crop forms a belt varying in width from 5 to 25 miles. The invariable 
position of this belt on the outer edge of the Lower Cretaceous area 
leaves no room for any reasonable doubt that it is composed of the 
beds lying at the base of the formation ; but apparent dips have proved 
confusing and unreliable, so that I have no confidence in any estimate 
of the total thickness of strata represented by the outciop. I incline 
to the belief that on the whole the angle of dip is very low — perhaps 
in many instances no more than the fall of the ground. However, an 
