408 
An admirable description is given of the Eolling Downs Beds, as they are 
developed in South Australia, in a Paper on “ The Mesozoic Plains of South Australia,” 
by Mr. H. T. Lyell Brown, Government Geologist of that Colony, read before 
the Australasian Association for the Advancement of Science,* from which a few 
extracts may with advantage be made in this place. 
“ The area over which the Mesozoic beds form the surface rock, or are only 
thinly covered by those of Tertiary formation, extends east from the boundaries of 
New South Wales and Queensland, westward to the boundary of Western Australia; 
northward it is bounded by the Musgrave Eauges and Lat. 26°, and southward by 
an irregular line extending from the northern edge of the Nullarbor Plains in Western 
Australia, round by the Warburton Eangc and the northern extremity of the main 
range to the vicinity of Lake Frome, near which it passes into New South Wales. 
Here and there along the telegi'aph line from Hergott Springs to the Peak and 
Charlotte Waters, the Dennison, Margaret, and other ranges, composed of Primary 
rocks, protrude through it in the form of islands, rising above the general surface in 
places to a height of 1,000 feet or more.” .... “The general level of this vast 
territory varies from some two hundred feet above sea-level to twenty five or thirty feet 
below it, in the case of Lake Byre.” 
After describing the “ Table-land and Table-hill country ” and the “ Stony 
Downs,” which he refers to as “either of Tipper Cretaceous or Lower Tertiary age,” 
Mr. Brown continues as follows : — 
“ Below and surrounding the table-hills and stony downs, are the soft silt 
plains, which, together with the former, cover the gypseous clays, marls, calcareous 
shales, limestones, sand, and gravel drifts of Cretaceous age. The greatest thickness 
of these beds, which has beeu proved by boring at Tarkiniuna, is about 1,200 
'■ Bores have been sunk by the Government in this forma- 
tion at Tarkininna, where artesian water was tapped at 1,200 feet, and at 
Hergott, Coward Springs, Strangway Springs, &c., where a large supply of water 
was attained at an average depth of some three hundred feet. The supply from 
some of these bores is over a million gallons per day.” . . . . “ The fossils which 
occur in this formation are found in masses and nodules of limestones, and in the 
calcareous shales, but generally they are most plentiful in the former, which are often 
entirely composed of them.” 
It is very satisfactory to have our long-entertained view of the age of the 
Eolling Downs Formation of Queensland confirmed, as regards the extension of the 
same formation into South Australia, by such a competent authority as Prof. Ealph Tate, 
of Adelaide, who, iu a Paper “ On the Age of the Mesozoic Eocks of the Lake Eyre 
Basin,” f maltes the following remarks : — 
“ The occurrence of Orioceras and a Ceratite-like Ammonite among the common 
fossils of the Lake Eyre Basin demands their relegation, as also those of "Wollumbilla, 
to the Cretaceous System ; ” and again : — “ The European identities alleged to occur in 
the Wollumbilla beds, are Linyula ovalis, Avicula hramnhui'ieiisis, Helemiiites paxillosus, 
Serpula intesHnalis, and Uliynchonella variabilis. Eclying on Mr. Moore’s determina- 
tions, I have persistently advocated the Jurassic age of the Lake Eyre fossils; but, 
forced to abandon that position by the more decided Cretaceous facies of recently 
acquired species, it becomes necessary to reinvestigate the claims of the fore-mentioned 
species to bear the names attached to them.” 
* Proc. Auetr. Assoc. Adv. Sci., 1888, i., p. 241. 
t Ihid., p. 228. 
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