08 Here are the rocks I told you about. They have these very distinctive
circular and oval holes in them and there are plenty of these features
here. The Ordnance Survey reference for this is NX405824.
I sent an enquiry to the Geological Society asking if someone could explain
how these features were formed. This society are just now (autumn 2009)
adding a new page to their website which allows you to "Ask
In the meantime I have been given a comprehensive explanation of the phenomenon
- which boils down to the fact that these holes were once filled with
calcium carbonate which is softer than the greywacks sandstone in which
you see them here. The calium carbonate has dissolved away leaving only
the ghost of it's presence written into the stone. The distinctive raised
rings round the mouth of the holes seems to be of particular interest
to the geologists.
You can see the full answer to my question on the Geological
You can see what looks like this same washing out of softer rock from
the host rock on Ardwall
Island, though in this case the holes left are much smaller, and being
by the sea are not so surprising as when you find them on top of a hill.
Some other impressive geological features in Galloway shown on this site
are to be found at the "Devil's
Bowling Green" on Craignaw, on the Rig
of the Jarkness and between Big
Gairy and Meikle Mulltaggart - though these are more to do with the
effects of glaciation.
You can also see the house where Charles
Lapworth stayed at Birkhill in the Moffat Hills - he made significant
contributions towards unravelling the geology of the Southern Uplands
and was a much honoured geologist. These Moffat Hills particularly around
Skene which were his stomping ground also offer outstanding classic