Editing Australian Capital Territory (section)

===Geology===
{{main|Geology of the Australian Capital Territory}}
Notable geological formations in the territory include the ''Canberra Formation'', the ''Pittman Formation'', ''Black Mountain Sandstone'' and ''State Circle Shale''.

In the 1840s [[fossil]]s of [[brachiopod]]s and [[trilobite]]s from the [[Silurian]] period were discovered at Woolshed Creek near [[Duntroon, Australian Capital Territory|Duntroon]]. At the time, these were the oldest fossils discovered in Australia, though this record has now been far surpassed.<ref>{{citation |title=Entry to the ACT Heritage Register – 20010. Woolshed Creek Fossil Site |url=http://www.environment.act.gov.au/Files/heritageregister20010.pdf |archive-url=https://web.archive.org/web/20051022162853/http://www.environment.act.gov.au/Files/heritageregister20010.pdf |publisher=ACT Heritage Council |archive-date=22 October 2005}}</ref> Other specific geological places of interest include the State Circle cutting and the Deakin [[anticline]].<ref>{{cite AHD|105733|State Circle Cutting}}</ref><ref>{{citation |title=National Trust of Australia – Deakin Anticline |url=http://www.act.nationaltrust.org.au/places/deak-anti.html |archive-url=https://web.archive.org/web/20040706073745/http://www.act.nationaltrust.org.au/places/deak-anti.html |archive-date=6 July 2004}}</ref>

The oldest rocks in the territory date from the [[Ordovician]] around 480 million years ago. During this period the region along with most of Eastern Australia was part of the ocean floor; formations from this period include the ''Black Mountain Sandstone'' formation and the ''Pittman Formation'' consisting largely of [[quartz]]-rich [[sandstone]], [[siltstone]] and [[shale]]. These formations became exposed when the ocean floor was raised by a major [[orogeny|volcanic activity]] in the [[Devonian]] forming much of the east coast of Australia.