104 SUNKLANDS OF PORT PHILLIP BAY AND BASS STRAIT 
In the Maribyrnong River, which flows into the Yarra just 
before the latter empties into Hobson’s Bay, the river terraces 
were formed, according to Keble and Macpherson (1946), by the 
vertical erosion caused by the eustatic fall of sea level; if tilting 
had any influence on this vertical erosion, it was subordinate to 
that caused by eustatic adjustment. They found that there were 
three main fliiviatile terraces which appeared to them to have 
been formed during the fall of sea level at each of the three Wurm 
glaciation maxima. The fall of sea level during the first maximum 
(Wl) entrenched the Keilor Flood Plain and formed the Keilor 
Terrace ; during the rise of sea level in the succeeding interglacial 
stage (Wl/2) the Braybrook Flood Plain was formed; it was 
entrenched by the fall of sea level in the second glaciation (W2), 
and during the succeeding interglacial stage (W2/3), the Maribyr- 
nong Flood Plain was formed, and entrenched by the fall of sea 
level during the third glaciation (W3). This last entrenchment, 
together with the Footscray Warp (Keble and Macpherson 1946), 
partly supplied the material for the Yarra Delta, which was 
submerged by the 15 to 20 feet fall of sea level. The subsequent 
fall of sea level is indicated by entrenchment above tide limit in 
the Maribyrnong River. 
Correlating these fliiviatile cycles with the fluvio-estuarine 
cycles of the Nepean Bay Bar, the sediments on the 35-fathom 
platform from 153 feet to 210 feet in the Wannaeue Bore are 
taken to be the downstream extension of the Keilor Flood Plain, 
and the drift on the 45-fathom platform from 256 feet to 262 feet 
(the bottom of the bore) as the downstream extension of the sub- 
basalt sands under the Keilor Plains basalt. The Keilor Flood 
Plain and the fluviatile sub-basalt sands which were contem- 
poraneous with the flood plain deposits of the middle Dandenong 
Creek are representative of the most sustained cycles in the 
physiography of the Yarra River System. The 35-fathom and 
45-fathom platforms were surfaces exhibiting mature fluviatile 
erosion following the retreat of the sea from the Bay Bar. The 
maturity of the erosion, and the streams responsible for it, 
together with the place of the fluviatile deposits in the strati- 
graphic sequence justify the correlation: no other fluvio-estuarine 
deposits in the bore records could be correlated with this fluviatile 
erosion. 
The following table (Fig. 15) is an attempt to correlate the 
records of the bores with the glacial and interglacial stages of 
Europe, America, and elsewhere in Australia, particularly in 
Tasmania; the correlation of David Tindale (1933), Lewis (1933, 
1934), Edwards (1941) and David (1924), are included. 
