Most likely E. mannifera; there are several around that area which are multi-stemmed, multi-stemmed (re) growth is most likely the result of fire; there are magnificent E. mannifera for instance a bit further south west. Visit FoMM tree album https://www.flickr.com/photos/61627737@N03/albums/72157627244893256 to see how to distinguish from Scribbly gum. E blakelyi don't grow in that steep shallow soil.
Waltraud this is E.rossii, you can see furrows of bark underneath the limbs even though the photos aren't particularly sharp. In my experience both are equally common on Mt Majura.
With furrows do you mean the pressure lines? I can't really see them; perhaps something on the bottom of the most right-hand trunk? I will go and check the tree/s when I have the time.