Can you tell us if this skink was small (less than about 10 cm total length including tail) or medium in size (say around 20cm total length including tail). I suspect this is not an Egernia species or Liopholis species because it lacks prominent ear lobules on the front side of the ear opening.
Well spotted Will, I must confess I missed the absence of ear lobes. 18-20 cm seems a bit long for entrecasteauxii but that seems the only other possibility based on the image? Have you any other suggestions?
I agree with John, I think the only thing this can be is a P. entrecasteauxii. They can look quite large for a small skink. The good close up photo gave me and others an impression of a very large skink. I have seen them often at this location (the Mt Gingera Track head near Mt Ginini). They are often this very dark colour up in the Brindabella/Bimberi range area.