120 PROCEEDINGS OF THE ROYAL SOCIETY OF QUEENSLAND. 
The recognition in the Petrie Series of so many of the same species 
as are found in The Narrows Tertiaries also suggests similar environ- 
mental conditions of deposition for the ostracod-bearing shales in both 
these Tertiary basins. (For a detailed account of these, see above.) 
Finally, the discovery of Ilyodromus? concentricus in the material 
from Houghton’s Bore near Lawnton has been of particular importance, 
since this species proved to have a vertical range of only 115 feet in 
The Narrows Tertiaries. Accordingly, the ostracod-bearing shale encoun- 
tered at about 45 feet in Houghton’s Bore may reasonably be correlated 
with some horizon within this 115-foot thickness. Furthermore, as this 
species has been found to be quite common in the Lawnton material, it 
may be stratigraphically equivalent to an horizon somewhere near the 
central part of the Zone of Ilyodromus? concentricus in The Narrows 
Tertiaries. It has, therefore, been possible to correlate a horizon in the 
Petrie Series at least approximately with an equivalent one in The 
Narrows Tertiaries. 
C. Baffle Creek. 
General Aspects. 
Immediately before and during the early part of the 1914-1918 war 
some consideration was given to the possibility of exploiting the oil shales 
of the Baffle Creek Tertiaries, and a number of shafts and a deep bore — 
the Lowmead No. 1 Bore — were put down in the southern part of the 
basin. A small collection of samples from some of these sinkings are now 
in the Museum of the Department of Geology, University of Queensland, 
and have recently been examined by the writer. All the shale samples 
in this small collection are somewhat bituminous in nature, but ostracods 
have not been found in all the specimens. In some, however, they have 
been found to be exceedingly abundant, and so closely packed that it is 
impossible to distinguish the individual outlines of the valves 
accurately. 
The Baffle Creek Tertiaries, situated in the upper part of the Baffle 
Creek valley, about midway between Bundaberg and Gladstone, are 
known to occupy a belt of country some eleven miles long and one to 
two miles wide, and to have a probable area of some thirty square miles. 
They extend from near Lowmead (48 miles N. of Bundaberg) almost to 
Colosseum (6 miles S. of Miriam Vale) on the main North Coast 
Bailway. 
As well as ostracods, Ball (1916, p. 15) has recorded indeterminable 
carbonised stem fragments, sponge gemmules, freshwater gastropods and 
chelonian remains from the Tertiary shales, and dicotyledonous leaves 
and unionids from the associated argillaceous sandstones in the basin. 
Ball (1914a, p. 21) has also stated that the Baffle Creek “shales 
closely resemble those of the Oxley district, near Brisbane, not only in 
lithological characters but in their fossil contents.” 
The ostracod-bearing shales examined are all from portion 30, parish 
of Warro, county of Flinders. A number of them are from various 
depths in the Lowmead No. 1 Bore, which was put down in the N.W. 
corner of portion 30, about a quarter of a mile from the railway and 
some two miles W.N.W. of Lowmead railway station. Several of the 
samples are from No. 2 Shaft, in the centre of portion 30, near the 
