Meant to add this quote:

"Geographically Tonduff is interesting because the sources of three East coast rivers start on the southern flanks of the mountain: the Liffey, Dargle and Avonmore. "

http://www.mountainviews.ie/mv/index.php?mtnindex=206

If that's granite, there's gotta be a low percentage score attatched to the possibility of them being natural.

But I've banged rocks on granite, and it doesn't seem particularly likely that anyone could get that tightness of contour woithout years of patient grinding. I'd agree that these have to be the work of metal tools.

Dunno about Peter's 100yr limit though, the edges look a bit too softened for 100yr steel on granite. Could be some of those feet-type things, which is a mild synchronicity, as just after I read this yesterady, It made me thinnk of foot carvings, and then, stright after, I happened to re-read a review of this:
http://www.bordbooks.co.uk/footprints.html

Better picture here
http://www.sliabh.net/index.php?p=224