Metropolitan Melbourne Investigation Discussion Paper - Victorian ...

The basement rocks also provided more undulating
topography, such as Richmond Hill, which became
sought after residential locations; fl atter volcanic plains
were left for industry including pastoral runs, and
settlements for the working class. The Collingwood
fl at is situated on heavy clay soil derived from a Newer
Volcanics basalt fl ow. With ready access to the Yarra
River as a drain, this area soon became a focus for
those industries specialising in noxious waste such as
tanneries, abattoirs, soap and candle manufacturing
and wool and sheepskin production. 34,35
Newer volcanics basalts are resistant to weathering
and were recognised as an excellent building material.
This rock is used extensively throughout the region,
and known as bluestone and blue metal. The fi rst
quarries, which opened in the 1830s and 1840s, were
located in the Fitzroy Gardens, Carlton and Clifton
Hill. 33 Other building materials were tried over time,
including the Permian age sandstones quarried at
Bacchus Marsh. Many of these were found to weather
over time and proved to be far less suitable than
other sandstones procured from more distant areas
of the colony such as the Grampians. Tasmanian
sandstone was used extensively in early buildings.
Other building materials such as sand and gravel
were readily available in a number of locations (e.g.
Lilydale toppings).
By far the greatest geological infl uence on Melbourne’s
development was the discovery of gold in Warrandyte
in 1851. Soon followed by discoveries in the gold
fi elds at Ballarat and Bendigo, the riches this mineral
resource brought to the city of Melbourne had far
reaching effects on the development of the city (see
chapter 3).
Left: Old Treasury Building Melbourne (1856-1858)
is constructed with a basement and ground storey of
bluestone (basalt) quarried from Footscray. The above
ground façade is mostly sandstone from Bald Hill,
Bacchus Marsh. The Old Treasury Building is signifi cant
as one of the earliest undertakings by the Public Works
Department and was designed by architect J. J. Clark in
the Renaissance Revival style (VHR 1526).
2.1.2 GEOMORPHOLOGY OF THE
MELBOURNE REGION
Victoria has a diversity of landscapes formed by variations
in geomorphological processes across variable topography,
geological history and rock lithology or composition. In
addition, climate and sea level changes have also played
a role in forming the land surface we see today. 26 Victorian
geomorphology has been described in terms of regions
and smaller units of differing character on a regional or
local scale. 36,37 This section describes geomorphological
landforms and processes within the Metropolitan Melbourne
Investigation area.
Geomorphological regions
A statewide geomorphological framework has been
developed by the Geomorphological Reference Group
(GRG) and the Department of Primary Industries (DPI),
building upon work started in the 1960s by the Soil
Conservation Authority. Under this classifi cation, the
investigation area encompasses the six regions described
below and shown in fi gure 2.2.
Eastern Uplands
The Eastern Uplands form the Victorian section of the Great
Dividing Range encompassing the drainage divide; that is,
the area separating streams fl owing inland to the Murray
River from those fl owing south to the coast. In eastern
Victoria the uplands are a prominent and rugged mountain
region, but much of the western part is at lower elevations.
There are also areas of low relief comprising elevated
plateaus (Kinglake surface at 275 metres elevation, Bogong
High Plains at 1500-1600 metres elevation) as well as highly
dissected valleys along the northern and southern slopes.
The Yarra River fl ows southwest from the Eastern Uplands
to Port Phillip Bay. The elevated topography of the northern
and eastern regions of the investigation area is part of the
Eastern Uplands (fi gure 2.2).
Western Uplands
The Western Uplands extend from Kilmore Gap north
of Melbourne westwards towards the Victorian-South
Australian border, as a low-relief drainage divide with an
average elevation of about 300 metres. A small area of the
Western Uplands occurs in the northern and western part of
the investigation area from Toolern Vale, north of Melton, to
Riddells Creek. The Maribyrnong, Werribee, Lerderderg and
Moorabool Rivers fl ow southeast from these uplands. Rock
type and structure strongly controls landform in the Western
Uplands. The southern margin has been buried by the
extensive lava fl ows of the Volcanic Plains in many places.
Volcanic eruption centres within the Western Uplands have
produced valley-fi lling lava fl ows and lava plateau which
may have developed waterfalls, such as Trentham Falls and
Lal Lal Falls.
25