RIVER YARRA, VICTORIA 25 
to the present Yarra River system. From Research for ten miles 
northwards (measured in a direct line) the hill summits are 600 
ft. to 650 ft. For a similar distance in an east-west direction the 
same holds. This proves that the pre-Older Basalt terrain was a 
peneplain, and the river flowing over it was mature in that part 
at least of its course. 
Diamend Crean 
Kangaroo Ground 
OB. Residual 
Querfzites 
> 
y Walsons Crean 
Western 
RA PLATEAU 
SECTION FROM DIAMOND CR. TO YARRA FLATS 
FIG. 4b 
Section drawn from contours of Military Map, Yan Yean and Ringwood 
Sheets, showing the relationships of the Yarra Plateau and Nillumbik Pene- 
plain levels at Yering Gorge. 
These facts also show that the Kinglake Escarpment is a very 
old feature. The cutting back of the escarpment was effectively 
retarded by the formation of the Older Basalt lava field. The 
rapid back-cutting of the scarp could not be re-initiated until the 
lava field had been removed. This has been done and the streams 
are now actively cutting back into the escarpment. 
The terrain represented by the summits of the hills, and covered 
in places by Older Basalt or associated fluviatile deposits, is the 
terrain (Gregory’s “shelf””) which is to be known by the term 
Yarra Plateau. However, it does not reach as far south as the 
Mitcham Axis but terminates at Research. 
3 i $ ef . ¡Bu 
| : E H P sg 
Section drawn from contours of Military Map, Ringwood and Yan Yean Sheets, 
showing the relationship of the Nillumbik Peneplain and Yarra Plateau to one 
another and the Kinglake Escarpment. 
THE NILLUMBIK PENEPLAIN 
When Jutson (1911) extended the Yarra Plateau from Greg- 
ory’s Queenstown-Christmas Hills-Mooroolbark line to include 
the “Croydon Senkungsfeld" (i.e., the Croydon Lowlands and 
Yarra Flats) he gave the feature the new name of Nillumbik 
Peneplain (p. 477). Hills (1934, pp. 167-168, 173) adopted this 
term chiefly for the level of the stripped fossil plain, remnants 
