From the profile for David Thomas curated by Jenna:
"The foregoing account gives all the significant facts about the life of David Thomas that could be ascertained. On 3 Oct 1689 administration on his estate was granted to his widow Joanna (Haskell. Prob dau of Roger)"
From the notes in http://www.pcez.com/~bigshoe/dt/Blan/soule.html#2139
"(2138) David Thomas' death record is not in the vital record book, however I do have the inventory here with the date of 12 Dec. 1689. It says,
'Joanna relict widow of the within : named David Thomas (can't read this word) approved before William Bradford Esq.'
then goes on to name the others. It seems Joanna inherited the whole of it, quite unusual in those days. (2139ix) Mary and (2139iv) Joanna Thomas are both listed in Boston Vital Records on pgs. 156, 161 and the dates are assumed to be the date they were submitted and not their date of birth. There are no gravestones for the parents (2138) David and (2139) Joanna.
In the book 'Thomas Families of Plymouth County, Mass.' written by John Marshall Raymond (Thomas Family Publications, 1980) has a reference in the notes that say (2139) Joanna (Davis), I believe Davis is in reference to one of the contributors of the book and not her maiden name."
-- Janet Griffith c/o
http://genforum.genealogy.com/thomas/messages/15416.html
"from TORREY:
"(2138) THOMAS, David (-1689) & (2139) Joanna _____ (-1689+); by 1649; Salem/Middleborough {Middleborough Hist. 53; MD 1:221;Thomas (#2) 1; Pilgrim Notes 5:21; Gen. Adv. 1:73; Holman Ms: Vaughan 11}"
-- http://worldconnect.rootsweb.ancestry.com/cgi-bin/igm.cgi?op=GET&am...
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Therefore, the wife of David Thomas was a Joanna, parents unknown, and probably not Joanna, daughter of Thomas Davis, of Haverhill