I haven't found anything either, but two _Mark Twain Journal_ articles
offer possibilties on where you might wish to look:

1) Isabelle Budd's (fall 1985) investigation of "The Relation of Mark
Twain to Cyril Clemens" cites as sources Raymond Martin Bell's 1984 _The
Ancestry of Samuel Clemens, Grandfather of Mark Twain_ and P. O. Selby's
1973 (Northeast Missouri State U.) _Mark Twain's Kinfolks_.

2) Lucius M. Lampton (another Twain cousin) wrote of Twain's Lampton Kin
(fall 1989).  You might try his _The Genealogy of Mark Twain_ (1990).

The two _Journal_ articles do not have the answer to your question.  I
have not located the cited books.

larry marshburne                     [log in to unmask]