The major outcrop
5000 years of toolwork does this to a stone.
Close-up of another outcrop showing different tool marks. I've identified the different markings in the B&W photo.
These stones show the grooves left by the local Mund-gah clan as they sharpened their axes and spears, and ground the seeds for flour. "Ground Edge" technology is one of the oldest in the world and was a development of the "struck stone" tools. The Aborigines decided banging the rocks together was a little too crude.
The Terramungamine stones show use dating back 5000 years. This is a sigificant, but not sacred, site and is open to the public.