77 
SUNKLANDS OF PORT PHILLIP BAY AND BASS STRAIT 
Nepean Bay Bar 
HI. Evidence of Sorrento, W annaeue and Other Bores on Nepean 
Bay Bar. 
The Sorrento Bore (Fig. 5) was put down in 1910 by the 
Geological Survey of Victoria, on the Nepean Peninsula at the 
north-east corner of the Sorrento Recreation Reserve (Water 
Reserve, allot. 6A, Parish of Nepean), the bore site being 10 
feet above sea level. The reduced levels of this and other bores 
are given here with the letters L.W.M. — low water mark Hobson’s 
Bay — the datum usually adopted in Victoria. Incidentally, it 
may he mentioned that all deductions as to tectonic or other 
movements are based on L.W.M. 
The drilling of the Sorrento Bore was done partly with a 
calyx bit to obtain a core, and with a core barrel when the sedi- 
ments were uncompacted. Core samples were obtained at the 
depths indicated by Chapman (1928) in his report on the palaeon- 
tology of the bore. It was put down, as Chapman states, on the 
downthrow side of Selwyn’s Fault and gives, according to him, a 
“succession of the Tertiary beds in the most complete form obtain- 
able, since in no other spot would there be such a continuous and 
extremely thick deposit of practically the whole Tertiary Series.” 
Hitherto, the information available as to the age of the Upper 
Dune Series, the surface deposit of the Nepean Peninsula, was 
meagre. A small portion of the Nepean Bay Bar — ^that eastwards 
for a few miles from Point Nepean — came into Quarter Sheet 
29 N.E. surveyed by Daintree in 1861, who, following the advice 
of McCoy, mapped it as Newer Pliocene. The major part of the 
Quarter Sheet covers an area west of The Heads, and shows that 
the Upper Dune Series extends across that fairway. Daintree 
(1861-2) states in his report on the sheet that a skull of a wombat 
was found while the face of the cliff at Queenscliff was being 
removed. There is no doubt that the skull and lower jaws of an 
extinct Eared Seal described by McCoy (1877) as Arctocephalus 
williamsi came from the Upper Dune Series at Queenscliff. Dr. 
Williams, who sent it to McCoy, stated in his letter “it was found 
5 feet below the surface in what was described as marl and sand- 
stone, overlaid with limestone and sandy loam”: dune limestone 
is the only calcareous bed that occurs at or near the surface in 
this part. With it was found the remains of an extinct wombat 
Phascolomys pUocenus (McCoy) and the Tasmanian Devil Sar- 
cophilus ursinus (Harris), now extinct in Victoria but still living 
in Tasmania. McCoy (1877) states that Arctocephalus williamsi 
was found in the dune area at Cape Otway, but does not say in 
