August, 1938 
The Queensland Naturalist 
103 
beach sand, especially at and above the high tide mark. 
These perhaps are residual products from the old 
Palaeozoic rocks of South-Eastern Queensland and 
Northern New South Wales, and contain rutile, mag- 
netite, ilmenite, together with minute amounts of gold 
and perhaps platinum. 
Jensen ascribes the source mainly to the dis- 
integrated igneous intrusions. 
The geology, as indicated above, is of considerable 
interest, and although more varied, is similar in many 
respects to that of the Noosa Headland some 10-12 miles 
further north. 
MESOZOIC SEDIMENTS 
These are sandstones, grits, fine conglomerates and 
shales, very similar lithologically to other occurrences 
in South-Eastern Queensland. At Points Arkwright and 
Perry, they appear to be more or less horizontally dis- 
posed. Sandstones predominate and often show very 
much current bedding, suggesting deposition under 
estuarine conditions. Most of the sandstone, and 
especially the shaley material, has been much impreg- 
nated with limonite. 
Recognisable fossil plant remains were not seen, but 
petrified wood is common along the foreshore. At 
Petrie’s Creek, Nambour, the sediments contain Thinn- 
f el dia odontoptcroidcs , associated with a thin coal seam, 
while between Cooroy and Tewantin shales containing 
Elatocladus planus have been found. The sediments in 
the opinion of some are to be assigned to the base of the 
Walloon, rather than to the Ipswich, series and, if so, 
would have to be regarded as Jurassic in age. 
Some of the sandstone layers at Points Arkwright 
and Perry have in them rounded to subangular patches 
of carbonaceous shale or shaley sandstone incorporated 
in a breccia-like manner. This occurrence is not un- 
common, and is rather striking, so that the question of its 
origin excites the interest of many. Perhaps it results 
from the deposition of layers of mud on a loosely coherent 
sandstone stratum. The former, after desiccation and 
compaction, becomes submerged by a further deposit of 
sand, and then becomes broken and brecciated under the 
load. . Ultimately, the whole lot is cemented into the 
brecciated mass which is exposed to-day. 
PEAT SANDSTONE 
North from Coolum Beach, along the foreshore is a 
development several feet thick of recent sand, cemented by 
a peaty material. This outcrop on the strand line may at 
