>>>>>There is a cupmarked boulder in Denmark (but can't find a link) that has a line of deep cups, about a dozen, that would fit the description.
how about this at Fowberry? Not very deep, though. http://www.themodernantiquarian.com/post/14595
+ http://groups.msn.com/rockartinthebritishlandscape/projects.msnw
!
When I see the term 'Dating Rock Art' I smile and fondle the nearest carved boulder (just out of reach with a pile of unopened junk mail on top).