NOTES ON THE PETRIE SERIES, SOUTH-EASTERN QUEENSLAND. 99 
In conclusion, it seems that the yield of crude oil from typical 
Strathpine oil shale varies between 5 and 20 gallons to the ton. That 
is, it is mainly a low grade oil shale. Moreover, it seems that the seams, 
instead of being continuous throughout the series, may be of restricted 
areal extent and generally lenticular in shape. To determine the quan- 
tity of oil shale present, furthermore, a systematic boring campaign 
would have to be undertaken, and this, in view of the low-grade nature 
of the material, the relative thinness of the seams, and their steeply 
dipping nature, does not appear to be warranted at the present time. 
It must be presumed, however, that the steep dip of the outcropping oil 
shale referred to above decreases progressively as one proceeds away from 
the faulting, but this diminution in angle of dip may only be gradual, 
and so, even disregarding the nature of the material, mining operations 
would hardly prove economically feasible. In fact, the only favourable 
factor about the Strathpine oil shale is the convenient geographical 
location of the deposit, so close to the city of Brisbane. 
VI. GENERAL STATEMENTS AND ACKNOWLEDGMENTS. 
A number of other observations, which seem worthy of record, have 
been made during the course of geological work in this area. 
A considerable amount of greenish-white impure limestone has been 
found on the spoil heap of Francis’ well on portion 12, parish of Warner, 
near Four Mile Creek, and similar limestone has been collected from 
Brecknell’s bore, approximately half-a-mile to the S.S.W. From the 
rough log provided by Francis and the relative proportions of the 
various rock types on the spoil heap it would seem that approximately 
8 to 10 feet of this limestone was passed through in sinking the 55-feet 
well. Similar impure limestone has also been brought up (Ball, 1932, 
p. 384) from Simpson’s well in portion 186, parish of Nundah, near 
Bracken Ridge, the bed here being 12 feet in thickness. As freshwater 
limestone is really not a common rock, and seeing that it is a prominent 
member of the Silkstone Series, to which Whitehouse (1940, p. 34) has 
recently given a provisional Miocene age, it was thought by the writer 
that these two limestones might possibly be comparable in geological 
age. Unfortunately, macroscopic and microscopic search failed to reveal 
any recognisable fossils in the Petrie Series limestone, so chemical 
analysis was resorted to in an attempt to show up any possible relation- 
ship. I am indebted to M. H. Gabriel, of the Government Chemical 
Laboratory, for the following analysis of the Petrie Series limestone, the 
results of which show a very close resemblance to those given by Dunstan 
(1913, p. 648) for the Silkstone Series limestone: — 
Petrie 
Series Limestone. 
Silkstone Series Limestone. 
(Simpson 7 
s Well, Bald Hills.) 
(Limestone Hill, Ipswich.) 
Per cent. 
Per cent. 
Moisture 
14 
. . 04 
Loss on Ignition 
434 
. . 43-8 
Silica 
6-7 
. . 5-7 
Iron Oxide 
1-7 
. . 0.9 
Alumina 
14 
14 
Lime 
26-8 
. . 27-5 
Magnesia 
19-2 
. . 20-6 
100-0 
100-0 
