A colleague has suggested that there is a belief that wall
anchors/ties/clamps/cramps - they go by many names - were used to mark
properties in the underground railroad.

Has anyone come across this belief? (I'm assuming it was just a belief).
Any reference to the belief in print would be very welcome!

With best wishes,

Pat
Research student, Department of Archaeology, University of York

--
Pat Reynolds
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   "It might look a bit messy now,
                    but just you come back in 500 years time"
   (T. Pratchett)