Sir William Johnson provided the information used in Burke`s Peerage and Baronetage. He claimed to have been
"m 1739 Mary, dau of John de Wissenbergh, of Montreal". I can send email copy of this whole page to anyone who would lke a copy.
All I can say to that Sir W. was full of Blarney!
But he did have to tell Burkes something and he probably knew that he was choosing his heir by putting Mary (Catherine) down and so making John his heir.
But things are not that simple.
Quoting King George III from the London Gazette of (15.Nov. 1755) which was the official paper to annouince such things the Barontcy was also for Sir W. "Heirs Male of his Body lawfully begotten". (This is also online just google "London Gazette).
So John was not entitled to be the lawful heir and I do think it is funny how my poor g-g-g-g-g-g-g-g-gradmother suddenly and very conveniently vaishes so timeousy.
If there were any sort of locally legal marriage (note in those days no such thing as common law wife and the term is not recognised legally in UK even now) between Sir W. and an Indian woman and that womans eldest son alive at the time of Sir W. death was the legal heir.
How wonderful it would be if the true current Baronet of New York is now a Mohawk.
There would be a lot to do. Find the true wife! Find the correct descendant and then get it accepted by the present incumbent and the Royal Family.