An old sea dog

As I was ambling along the shore-line this afternoon my eye was drawn to a skull that had been buried deep in a sand dune but had now been exposed by the recent high tides. The skull once belonged to a very large dog. How long it had been buried in the dunes I know not but it was sitting among the shells of an old shell midden and a similar midden excavated last summer on the other side of the river was Pictish in age. Maybe this is a very old sea dog indeed!
I do so enjoy a good skull, and a good mystery!