SUNKLANDS OF PORT PHILLIP BAY AND BASS STRAIT 83 
marls in the vicinity of Jan J uc. As the material compris- 
ing the Bay Bar is dune limestone, and the eastern head- 
land -ti^ relative upthrow side of Selwyn’s Fault south- 
west ot Cape Schanck — consisted of basalt extending some 
distance seawards, it is evident that most of the calcareous 
material came from Jan Juc. 
(c) A plentiful source of material. The headlands at Jan Juc 
weie attacked by current and wave action, and supplied the 
material for the extension of the spit; to this was added, 
trom time to time, material contributed by the River Yarra 
from its valley to the north. 
(d) A bay deep enough to ensure that the material came to 
rest at the end of the spit, and was undisturbed by the 
surface movement of the bay water. That this was so is 
evident from the subsequent formation of the Bay Bar. 
(e) The building inward and upward of the spit, its emergence, 
and the subsequent formation of dunes on its surface. 
This sequence is clearly shown bv the record of Bore No 4 
Wannaeue (Fig. 4) upwards from 210 feet (L.W.M.). That the 
directions of the current and prevailing wind now found in Bass 
Strait persisted throughout the Pleistocene are shown by the fact 
that Jan Juc is to the south-west. The headland when the Bay Bar 
formed was about 4 miles east of the existing shoreline. A note 
on Admiralty Chart No. 1695B states : 
“A current averaging from ^ to 1| knots will generally be found setting 
through Bass St. ; after Westerly winds, it sets to the Eastd. ; with and after 
Easterly winds, to the Westward. As Westerly and South-westerly Winds are 
the prevailing ones throughout the Strait, the current will generally be found 
setting to the East and North-east, its strength depending on the previous force 
of the wind.” 
Dannevig (1915) states that the flood tides enter Bass Strait 
from the west, north, and south past King Island, and the ebb 
tides pour out through the same channels. They assume a north- 
easterly direction on passing King Island: a northern branch 
pushes on past Cape Otway towards Port Phillip and Western 
Port, where small arms enter various inlets. The main body is 
swayed to the east and south-east towards the centre of the Strait. 
The current from the Southern Ocean presses against the southern 
coast of Victoria and King Island, and although its greater volmne 
is diverted to the south-east and south long before reaching land, 
sufficient force remains to establish a general “drift” through 
the Strait from west to east. This current is, in the open ocean, 
accentuated by the dominating westerly winds and as this wind 
direction prevails in the Strait to the extent of about 16,000 miles 
per annum, its influence will make itself felt also upon the local 
