549 
bands are formed by slow precipitation from springs charged witb siliceous matter, or 
are beds of fine volcanic dust subsequently cemented, there is no evidence, at present, 
forthcoming to show. Hot springs are frequently met with in those districts where 
volcanic action is or has been rife ; hence the siliceous hands occurring among the beds 
of the Cape may only he the indirect result of that activity which is conjectured to have 
taken place in the earlier stages of this period.” 
Mr. H. Y. L. Brown* thus describes the Cretaceous rocks as seen by him 
between the 139th parallel and the Queensland Boundary from Lat. 26 to Lat. 32 S. ; 
“ The strata consist of brittle clays and calcareous shales, with bauds of limestone 
and gypsum, clay, ironstone and ferruginous sandstone, and sandy beds ; they are, as a 
rule, originally horizontal or gently undulating, and have a thickness, so far as at present 
known, of three hundred feet to four hundred feet. Ooerhjinfj this formation are beds 
of sandstone, argillaceous sandstone, kaolin, grit, and qDohbly conglomerate, forming 
table-lands and hills almost invariably capped by a thin bed of yellow and red flinty 
quartzite or jasper-rock, the total thickness varying from one hundred to two hundred 
feet. The pebbles found in this conglomerate consist of agate, jasper, chalcedony, opal, 
and coloured quartz, flint, white and crystallised quartz, and fossil wood showing a 
brilliant polish or glaze. The composition of these Supercrctaceous beds is the same 
over wide areas, from the Warrego, in H^ew South Wales, to the Diamantina. The 
topmost bed of yellow flinty quartzite or porcelaiuised sandstones, which forms the 
capping of the table-land formation, varies in thickness from ten to thirty feet ; it has a 
conchoidal fracture, and sometimes shows an amorphous structure, at others encloses 
grains of sand or quartz pebbles (often coated by hyalite and opaline quartz), in which 
case it may be considered a conglomerate. This porcelaiuised rock is intensely hard, 
and its particles are at a tension ; the most common appearance it presents is that of 
hard red or yellow boulders fitting close together, splintered, cracked and jointed into 
rounded and. roughly prismatic shapes. It lies in patches on the argillaceous sandstones 
and clays, forming in some places a mere coating, in others a deposit of thirty or forty 
feet thick. Large and small cellular boulders and slag-like masses, with hollow 
stalactitic forms, are often found. 'Whether in masses or pebbles the rock is invariably 
glazed, so as to present a shining red or yellow surface. The most likely theory that 
can bo advanced to account for the formation and glazed surface of this rock is that it 
has been formed by the infiltration of siliceous water from hot springs into beds of loose 
sand or porous sandstone. The stalactite-liko forms of some of the specimens from 
Cooper’s Creek, the occurrence of siliceous cores round nuclei of cemented sand in 
loose sand, and fragments of quartzite cemented together by silica, seem to prove this. 
The downs which flank the table-lands and hills are undulating and level plains, covered, 
as a rule, with a pavement-like coating of blocks or lobbies, or a red and yellow glazed 
porcelainised quartzite and flinty rock resting on soft yellow and reddish clayey loam ; 
the glazing of these stones is also probably due to the action of siliceous water. The 
table-lauds and hills composed of these Suporcretaceous rocks are elevated to a height of 
some one hundred to two hundred and fifty feet above the level of the surrounding 
plains ; though generally horizontal they are sometimes iuclined at a low angle. On the 
I^ilpie Nilpie Creek the flinty quartzite forms steep bluffs, and also occupies the creek- 
flat below, and undulates beneath the soft silt flats. . . . The elevated table-lands 
find hills occupy the country north and south of Cooper’s Creek, in the vicinity of the 
eastern boundary line [of South Australia] to Haddon Station, near which place the 
range branches off eastward and northward into Queensland ; Kirby s Knob, Mount 
Report of Government Geologist. Adelaide : by xVuthority : 18S3. 
