Yes the diary, what has survived, is in the National Congress of American Indians Archives in Washington D.C.
Franklyn/Franklin "Elwatum" Bearce(? there are few spellings of this surname to same family line); in 1920'S or 30's submitted documents to Congress, for the opportunity that the Schagticoke Nation might be given Federal Status. Congress denied this request. In the 1950'S other "attempts" were made for such Fed. Recognition, eventually this request was honored, and the Schagticoke Reservation is in the area of Kent, CT. today.
Evidence provided ie "the diary remnants" were date analyzed, and some of the paper originated from the time(s) of the life of Zerviah Newcomb, known to have made paper, and also in a remote Parish, accounts for rude paper "of the day" owned by someone of "privilige".... this analysis in part played a key role in the reversal of the initial denial by Congress to grant this Nation "Recognition" by USA.
I am also a descendant of this Bearse line, through Simeon Gray/Grey a great, great, great-grandfather to my family. I am a member of the Oneida Nation, and of Mohican/Mun-see Nations.