|West of Port Phillip Bay|
The Barrabool Hills comprises a tilt-block of Cretaceous Otway Group sandstones and mudstones rising from approximately 20 m elevation to a maximum of 211 m along the northern edge (at Bayview). They are bounded to the north by the Barrabool Fault and dissected by tributaries of the Barwon River on the north and east of the block. Landforms are characteristically rounded hills separated by broad valleys. Drainage is weakly rectilinear, favouring south-east and north-east directions for the tributaries of the Barwon River (which bounds the northern edge) and the Waurn Ponds Creek (which drains the southern portion of the block). The Cretaceous hills south of Colac are an outlier of the Otway Ranges, forming a north-east to south-west trending ridge with a maximum elevation of 320 m. In places the dissection is pronounced (e.g. Escarpment Road) making the landform transitional to deeply dissected uplands (geomorphological unit 3.1.2).