I think they go back to the 18th century. Check out the 21 stones catalogued in 1994 by Joyce and Tar Riedinger. I located a cemetery this spring which can be found off Stone Store Mtn. Rd.in the town of Broome. Take a right off Rt.
Cemetery is approx.
4 miles up the mountain on the left. In some papers from other researchers I found references to several cemeteries that are not on your list. It may be that the name they are called is different than the actual place or they may have long been lost. I have found several cemeteries in the Blenheim area. Last visit, Henry Maham's stone was leaning on a tree and I couldn't find his wife, Catherin Maham, stone at all.