0 
beds, possibly from that, proved by drilling to exist in the Tertiary clays, but I can find no grounds 
whatever upon which to base any expectation of its existence in sufficient quantities to warrant 
the expenditure of money in drilling for it. 
A similar line of argument holds good for the Walloon country around Boonah, notwith- 
standing the fact that the geological conditions are somewhat more favorable over an area in 
the vicinity of Road vale. A little N. and W. of Road vale station Dr. Jensen pointed out to me 
evidences of subsidiary folding in the synclinal area occupied by the Walloon Series. Anticlinal 
folding exists, the closure of which may eventually be defined by mapping in sufficient detail; 
but, again, there is a complete absence of the presence of petroleum in places where 1 would expect 
such evidences. There are brine springs escaping from the lower members of the Walloon Series 
exposed near the road running from Wyaralong to Boonah, but the escaping salt water carries 
with it no evidences of the presence of petroleum. The beds are well exposed here in places ; 
igneous intrusions are numerous and often very considerable around the area, and yet they 
pierce the Walloon strata without carrying with them or allowing to escape any signs of petroleum. 
Apart from the structure the evidences are entirely negative, so that taking everything into 
consideration, the chances are considerably more than 100 to 1 against the finding of oil in profitable 
amounts, even should detailed geological work prove satisfactory closures to the structures that 
exist. 
III. LAGUNA BEACH, NEAR TEWANTIN. 
A. Geology. 
The 30-mile stretch of coastal sands forming a shallow curve between Noosa Head, at 
Tewantin, and the lighthouse -capped headland at Double Island Point, almost due N., is called 
Laguna Beach. Noosa Head owes its existence to dykes of andesite and a small boss of grano- 
cliorite, which are intrusive into grits which have been metamorphosed and hardened to an extent 
which enables them to offer good resistance to the action of the pounding sea. Double Island 
Point is a bold headland formed of tough andesitic lavas thrust well out from the main line of the 
coast, and looking very much like an island which the land has captured and with an outstretched 
arm is holding from the sea. This is literally true, for examination makes it very clear that 
Double Island was really an island not so very long ago, and has only become a peninsula within 
recent times. Between these two points is a flat stretch of, what I should call, dead sand dunes, 
a series of ridges formed entirely of loosely consolidated sands. They extend from the andesitic 
intrusion of Halls Hill, a few miles to the N.E. of Tewantin, northwards to the southern margins 
of Wide Bay, and are approximately bounded inland to the W. by the N. and S. line followed 
by the Noosa River and Tin Can Inlet. The dunes appear to increase in height and development 
as we proceed N. South of Wide Bay the old dune formations extend inland for, probably, 10 miles, 
I Laguna Beach and Ridges of Old Sand Dune Area from Double Island Point Lighthouse. 
Photo., A. W. 
and attain to elevations which exceed 800 feet above sea level. These old sand dunes have 
probably, some definite system of distribution and alignment, a knowledge of which would probably 
throw much light upon their origin and history. The existing topographical maps are not 
sufficiently detailed to render much assistance. Looked at from the beach they appear to form 
F.4101 . — 3 
