Well spotted Ken and a crackin' photo too.
I have moved the illustration to the correct page and posted Simpsons comments as a misc. item.

Simpson has a footnote on the page of the description
He states

'Dr Graves has, I am informed, made an important collection of analogous sculptures from stones and rocks in various parts of Ireland, and we may soon expect a full account of them from his able pen'

Any ideas about this?

Edit
I'm guessing Dr Graves is this fella
http://en.wikipedia.org/wiki/James_Graves_(antiquarian)

Then again it could also be Thomas Graves RN or Charles Graves.

cheers fitz