
630 RECORDS OF THE S.A, MUSEUM 
exposed sections of the earliest consolidated dunes so far known of the ‘*Present'’ 
series, indicates a relatively complex late history. 
When these dunes, as exposed at Glen Point and Cape Martin, were being 
developed an open beach shell fauna prevailed, This comprised dominant (hione 
and some Brachyodontes erosus, indicating presence of estuarine conditions, ‘True 
rock shells such as Turbo wndulatus were votable for their absence, It is probable 
that sea level was a few feet higher than at present, These dunes grew seaward and 
became indurated by caleareous consolidation beneath a red soil horizon, With the 
dynamic alterations brought about by slow maturing of the shore, perhaps com- 
plicated by minor eustatie fluctuations of sea level (such as are estimated to have 
occurred throughout Post-zlacial times), these dunes ave now being subjected to 
active erosion by the sea; they stand up as cliffs 20 feet high, fronting Cape 
Martin and Penguin Island. Commencement of this stage and consequent exposire 
of indurated dune rocks is indivated by the appearance of a mixed sand- and 
rock-shell fauna dominated by 7'urbo undulatus, The ‘*Present'’ shoreline is, 
therefore, a composite one with traces of an older, probably Post-glacial phase, only 
a few feet above present sea level, as well as the present-day dunes. 
WOAKWINE TERRACE, 
The 25 feet (7-5 metre) Woakwine Terrace has been traced in the field con- 
tinuously from east of the Glenelg River to Lake Alexandrina on the Murray River, 
a distance of 250 miles. [ts usual position is about three miles inland from the 
present coastline and its shore deposits and dunes extend inland in more than one 
line to widths of from three to five miles. Two series are conspicuous, with traces 
of a third between them. Inland trom Robe the {wo main series of dunes forming 
part of the Woakwine Terrace are particularly well defined. Locally they are 
known. respectively as the Woakwine and Dairy Ranges. Interdune lagoons 
forming Lake Hawdon and Woakwine, and Tea Tree Swamp separate the two 
ranges, The inland Dairy Range dunes in general are lower and more mature 
ihan the seaward Woakwine Range. They have a greater overburden of residual 
quartz sand, derived apparently by release and accnmuiation of quartz grains 
after leaching away of the surface of the limestone dunes. In places the interdune 
swamps between the two suites of dunes have been partly filled in with wind-blown 
quartz sand derived from the progressive decomposilion of range uplands. The 
shoreline forming the front of the Woakwine Terrace is defined by a continuous 
consolidated dune ‘‘range’? which varies from 200 to 100 feet in height, usually 
rising boldly from a beach which stands at approximately 25 feet (7:5 mictres) 
above L.W.O.8.T., Port Adelaide. Behind it is an older intermediate dune series, 
unnamed, against which it abuts, 
