The cutting near here exposes layers that are explained in the Historical Marker. (It does end with a small section of local social history.) The sign reads:
A glimpse into Canberra's ancient past
"Next time you drive down Tuggeranong Parkway, consider Canberra's ancient past. This two kilometre cutting, created during the building of the Parkway, reveals Canberra's ancient volcanic history and the evolution of its current landscape.
"The bottom layer, composed mostly of particles of quartz and feldspar, was formed in the Silurian period, 420 million years ago. High volcanoes on the present site of the Brindabella ranges erupted with explosive force, ejecting clouds of hot volcanic particles and gasses that descended in repeated ash avalanches, covering the land below.
"The white and purple sandstone and coarse grains of water-polished quartz in the layer above show that when the volcanoes quietened, eastward-flowing streams formed.
"The sediment they washed down blanketed the volcanic rocks and flowed into lakes and the sea. At times, the Canberra area was on ot near the eastern coast.
"Three more periods of volcanic activity followed, interspersed by quiet periods when rivers deposited purplish-red and grey sandstone and shale in lakes and on beaches. This sediment penetrated cracks and joints in the older volcanic rocks. The points of contact between these layers reveal how the force and speed of the ashflow disturbed these sedimentary deposits.
"You can also see where tectonic movement has folded and fractured these once-horizontal volcanic and sedimentary layers, inclining them obliquely towards the southwest. They appear in the road cut opposite.
"The cutting stands on farmland leased in 1928 to soldier-settler Guy Tanner, which he called Illoura. Guy married Frances (known as Brownie) in 1930. With Guy being a former jackaroo and Brownie's knowledge of the land and horsemanship, Illoura thrived. They, then their son Robert, farmed here successfully until 1970, when their lease was resumed for the Parkway.
"The road cutting was entered in the ACT Heritage Register in 2011."
Address: Heysen Street, Weston, ACT, 2611, Australia
Visited: 1721, Sunday, 2 September, 2018