This is posted as an artificial mound for want of a more appropriate term. The hill - Worm hill is a challenger for the mantle of the hill that was the dwelling spot for the Lampton Worm - see the Penshaw Hill Page. However, it does not have any rings and is therefore less likely to be so.
The hill itself give the appearance of a a natural hill which has had some modification. Local custom has it that this is an ancient site of significance and should be thought of as a potential ancient site.