Mt Rouse is an extinct volcano rising above the small town of Penshurst.  It stands as a distinct elevation about 100m higher than the surrounding plain.  There are clear views of the mountain from all angles, and from nearby peaks Mt Napier and the Grampians.

A detailed geological description is provided here and further information is located on the Volcanic features menu item to the left of this page.

Victorian Resources Online has a description of the mount with location and geological details.