Note: Mattapoisett was the southwest part of Rochester, Mass., until 1867 when it became a town of its own (source: familysearch.org research guides or whatever they are called. also Wikipedia.)
The source for the children's baptisms in the town records is "C.R. 2" which = 2nd Church of Rochester (Mattapoisett), according to the explanations on the first few pages of the book. (images 6 to 8 at ancestry.com)
John Wallace's birth date, Feb 16, 1750, is listed with his children's births and baptisms in the Vital Records of Rochester. But I don't think he was born in Rochester. 1) there are no other Wallaces in the town vital records except for his family. 2) The source for the date given in the book was not a vital record but "P.R.1 " = list of unmarked graves in Hammond Cemetery.
So more likely he was listed just because he was a resident registering his children's information. His wife Eunice Clark's birth record is in those records:
Eunice Clark, b 12 Sep 1755, Rochester, daughter of Ezekiel and Abigail.
as is their marriage:
Wallace John [on a duplicate record and intention spelled "Wallis"] and Eunice Clark, July 22 1781. source: PCR = Plymouth County Records
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from findagrave
Sgt John Wallis
Birth 16 Feb 1750 Rochester, Plymouth County, Massachusetts, USA
Death 1835 (aged 84–85)
Burial Hammond Cemetery, Mattapoisett, Plymouth County, Massachusetts, USA
Memorial ID 60706815
Inscription
Sergt. John Wallis 2 Mass. Mil. Rev. War
https://www.findagrave.com/memorial/60706815So findagrave's contributor concluded that John was born in Rochester, but they have been wrong before. The back of his headstone must give his birth and regiment in the Revolution, or at one time it was readable on the side in the photo.
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When I Googled 2nd Mass. Miitia, Revolutionary War, all I found was references to the 2nd Massachusetts Regiment. I am not a military expert by any means, so I don't know if they were the same.
https://en.wikipedia.org/wiki/2nd_Massachusetts_Regiment------------
He isn't in the DAR database of Revolutionary soldiers whose descendants have joined the DAR. Neither in Massachusetts nor Virginia.
https://services.dar.org/Public/DAR_Research/search_adb/default.cfm----------
This might help you find his Rev. War service, and fold3 might have the records themselves. I don't have a subscription to fold3.
National Archives Microfilm Publications
Compiled Service Records of Soldiers who served in the American Army During the Revolutionary War
https://www.fold3.com/pdf/M881.pdf-----------
He was in Massachusetts by 1781 and probably earlier if he served in a Mass. militia. He was called "Captain" throughout the Rochester records, so it seems pretty sure he was in the Rev. war. But "Sgt" on the headstone.
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Too bad you aren't looking for the Clarks. Someone has done them already. Eunice's father Ezekiel was born in Scituate MA, died in Rochester 18 Oct 1795, in his 69th year. He must have been married a few times, his widow when he died was Hannah. His will mentions a daughter Eunice, but not her married name.
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Where to go from here? I would find out as much as I could about his children and hope that one of their death records will name a specific place in Virginia for John's birth. I don't know anything about research in Virginia for that time period.
And/Or look for a heavy concentration of Wallace families in Virginia and try there. He probably was from somewhere on the Atlantic coast of Virginia. If he had gone too far inland and started farming, he probably never would have ended up in Mattapoisett, which is also on the coast.
