I managed to get to Forest Hills this morning, and found the 3 plots. Unfortunately 2 of them had no headstones, and the third had only one new'ish-looking one for the names Charles and Anna Twombly. This plot was the second of the three that was purchased, with the original proprietor being Jane Hadley (this would be John's sister). It is situated right next to a larger one that has John, his wife, his parents, and others.
I have copies of the 3 lot plans with individuals names, as well as a copy of the letter from Belle to the cemetery. The letter is basically requesting the list of names, as she had traced the family from 1683 to the present (Oct 1948). She also indicates that she is the last of the family line.
I did take some photo's of the plots themselves, although you may not find them so interesting without headstones.
If you send me an email to email@example.com
, I'll send you scanned documents and some photos.