In St. Joseph County the William Jefferson Family did not have a George. 1860 MI St. Joe, Constantne Twp. p. 383 William Jefferson 60 Laborer b-Eng Ann 50 b-Eng Thomas 19 laborer b-MI Susannah 10 laborer b- MI
In this family there is also a Samuel who was 5 in 1850 and Elizabeth A who was 11 in 1850 both born in MI.In 1860 they were living elsewhere in the county.
This may be your George- 1850 MI St. Clair Co., Port Huron Twp. P. 372 July 17 1850. 84/Charles Jefferson 31 b-NY Mary J.18 b-OH Catherine 10 b-Canada George W. 1 b-MI Mary A. Vanalstine 63 b-MD
I didn't write down Charles's occupation :( It either wasn't there or I missed it. Mary must be his second wife because Catherine is too old to be her child.It is possible that they lived in Van Buren Co., then moved to St. Clair.A lot of people from OH migrated to VB Co. I hope this helps. AS