Details from the Marrett House

This is an historic house owned by SPNEA (Society for the Preservation of New England Antiquities) of which I am a member.  It was built in 1789 and was lived in by the family until 1944 when it was given to the society.  One family member was Frances Marrett who worked at the Perkins School for the Blind in Boston and taught both Annie Sullivan and Hellen Keller.  The barn was spectacular.  So many interesting details but the one that fascinated me the most was the carved stone outside the front gate. (Extra) It was discovered in 1753 when the fort was built across the road by the earliest settlers.  It was moved to the Marret house over 100 years ago.  No one has any idea what it is.  Most speculate it is Native American in origin as the road was an important trail for local tribes.  Clearly not a natural formation, it has the appearance of a mounting block, but it remains a mystery.