Hanging Rock is said to be the best example of a volcanic plug in the world. It consists mainly of soda trachyte
rock, which apart from the Woodend District is found only in Norway and Sweden. Since it's formation, it has been exposed to weathering and erosion resulting in the unusual
rock formation.
It was made infamous by Joan Lindsay's novel "Picnic at
Hanging Rock"
Hanging rock is found 80km north of
Melbourne.