Old Pentland Watchhouse

This is the building where the Arnold Stones are stored, the watchhouse that was occupied by a guardian of the graves, to prevent unauthorised exhumation.

I was reminded of these stones following our visit to High School Yards yesterday, where a grave slab of an almost indentical type was unearthed during alterations to the site, which had been occupied by an early C13 Blackfriars monastery.

I wonder what is the connection.