128 . 
S.A. NAT., V'OL. XI\‘. 
August 31st, 193 J.. 
THE COAST FROM OUTER HARBOUR TO SELLICKS 
HILL. 
Geology and Physiography. 
(By C. Fenner, D.Sc,) 
An effort will here be made to give in simple terms an out- 
line of the chief features of the natural history of the coastal 
strip which runs from Pelican Point, at the northern end of Le 
Fevre Peninsula, to the clihs at the base of Sellicks Hill. This 
co\'ers a distance of 45 miles of coast — a strip of country full of 
varied and interesting features, physiographic, geological and 
botanical — most of it within walking distance of railway stations 
or tram-lines, and all of it easily reached by good roads from 
Adelaide — though the good field naturalist must always do tlie 
best of his travelling on foot. 
In order to set out the geology and physiography more clear- 
Iv, a rna-p of this 45-mile coastal strip has been prepared, and is 
set out herewith in four sections. In addition, a block diagram 
showing a section parallel to the cost from West Beach to hly- 
ponga is given on a separate page. This block diagram is in- 
tended to sItovv the simpler features of the structure and rock 
U'pes of the area. 
d'he first point that strikes the observer in his traverse from 
Outer Harbour to Sellicks Hill is a curious rhythm and repetition 
in the features seen. There are mangrove mud-flats, coastal 
sand-dunes, low cliffs of soft yellow and brown limestones, and 
higher cliffs with rocky and shingly beaches. 
d'he hard rocks of these cliffs are very ancient (Pi c-cambiian 
and Cambrian) and arc mostly dark-coloured quarmtes. A break 
one mile long occurs in these hard cliffs at Halletts Cove, lim- 
ning from Howchiii Ciully to the Field River. Then follows an- 
other tlirce miles of quite similar hard rock, with lemarkablc 
contortions of bedding in places. A mile of sand dunes occius 
where the AIorphett\'ale Creek comes to the sea, followed by 
cliffs of level-bedded limestones and mudstones, many of them 
beautifully coloured. 
Apart fiami the sand-dune break at the mouth ot the Un- 
kaparinga River, these gently-dipping, easily-eroded limestones 
continue for five miles until we come to the Moana sand-dunes, 
small in area, near the mouth of Pedlers Creek. Then follow two 
miles of cliffs of hard, ancient rock, four miles of the level- 
bedded limestone cliffs of Blanche Point and Aldlnga, then thiee 
miles of sand-dunes and sandy beach at Sellicks Beach, a 
area of tertiary limestone cliffs, and finally the high, hard cliffs at 
the base of Sellicks Hill extending to the south beyond Myponga. 
