The Skillion

The Skillion at Terrigal in the Central Coast Region of New South Wales is a striking landscape feature.

The sedimentary rock from which The Sillion is formed is known as the Terrigal Formation and was deposited ti the middle Triassic period. It is overlain by beds of Hawkesbury Sandstone a more recent sedimentary rock.

The most interesting feature of The Skillion is the difference in the way the feature has been weather on its southern and east faces. The east face is a sheer cliff face, while the south has been weathered into a more gently sloping cliff.

The Terrigal Formation sedimentary rocks were deposited in a river flood plain or delta and it is believed that the river which originally flowed to the southeast over time swung around to the northeast.

A further interesting feature at The Skillion is presence at the base of the southern cliff of a Palaeosol. Palaeosol is a former soil which has as the result of being buried beneath later sediments been lithified or turned into rock.

Within the Palaeosol are tubular structures which have been interpreted as the root casts of rushes which would once have grown on the river’s flood plain