Page:Quarterly Journal of the Geological Society of London, vol. 28.djvu/342

 The Burrum coal-seams, worked for some time on a branch of the Mary river, lie below the Maryborough Cyprina-sandstones ; and their relation to the Wollumbilla- and Gordon-Downs series has yet to be unravelled.

The idea which seems to offer the greatest amount of feasibility is, that contemporaneous with the deposit of a succession of marine beds to the westward of the dividing range, at a period in time extending through the Oolitic and part of the Cretaceous period, a vast lacustrine deposit was accumulated over a large area to the eastward of the same range, to which the sea obtained access after a very considerable thickness of freshwater beds had been piled up.

Beds of coal are a marked feature in these Mesozoic lacustrine beds, whilst their supposed marine equivalents to the westward are, as far as we have any observations on the subject, entirely devoid of that valuable mineral.

The appearance of these lacustrine coal-measures differs in a very marked manner from their supposed marine representatives to the westward. Coarse grits and thick-bedded sandstones form the majority of the strata, though shales, mudstones, and limestones are interstratified throughout the system.

The physical difference is even more marked ; level plains destitute of timber characterize the one, whilst broken ridges, covered in great measure with dense scrub and fine timber, are the attendant features of the other.

It is of great importance to the future of the colony to ascertain if the carbonaceous division of the Mesozoic formation is represented in any portion of the western plains between Wollumbilla and the Upper Flinders. If so, the coal-fields of Queensland would, indeed, be inexhaustible, and a stimulus might thus be given to the construction of that natural trunk-line of railway for Eastern Australia (first suggested by the Hon. J. Grant, late Minister of Lands in Victoria), from the Murray to the Gulf of Carpentaria. The necessity for this will become the more apparent when the rich gold- fields and mineral lodes of Northern Queensland are somewhat more developed, and when these western plains, the richest pasture in Australia, are fully stocked with cattle.

It is hoped that the determination of groups of fossils from the localities here mentioned may form bench-marks, so to speak, for future observers who may work this practically interesting subject to a more definite conclusion ; and the leading minds and students of physical science in the colony look with anxiety to the parent societies of England to aid them in their attempts to decipher the structure and past history of this great area, whose yet unrecorded facts must yield only to patient labour.

Mineral Springs. — There is one other subject of practical interest connected with the great western Mesozoic plains ; and that is the occurrence of hot alkaline springs, which suggest the possibility of obtaining supplies of water on the Artesian principle over some portion at least of this area.

At Gibson's Cattle-station on the Saxby river, a tributary of the