They aren't public records - these are documents that families would have in their possession; the deed could be handed down via will, but it's likely to be with whatever personal papers families have saved over the years. That's how my aunt has a Holy Cross deed for a plot bought by my greatgreat grandfather back in the 1840's. It is possible to prove ownership without the deed by showing direct descent or will(s). Does anyone know how to go about finding these deeds so possibly they can be claimed by decendents!