It may be interesting to note for some, that there were two very similar Thomas Jamesons who lived in colonial America at about the same time, with several striking coincidental similarities.
Our Thomas Jameson was born about 1710 in Ireland and immigrated to New England in 1738, setteling in New Hampshire. The other Thomas Jameson was born in 1732 in Virginia, the son of an Ulster born immigrant. Both of these Thomas Jamesons married girls with the surname Dickey, each of whom had fathers named John. Not only that, but the Thomas in Virginia also married, for his second wife, a girl with the surname Taggart. This is a surname known in the New Hampshire Jameson family too. In fact, Thomas Jameson's (NH) niece (Hugh Jameson's daughter) Elizabeth married a John Taggart.
No known relationship exists between these two Thomas Jamesons, nor any relationship between either of the two Dickey or Taggart families. Nevertheless these common similarities are interesting, to say the least.
A genealogy of this other Thomas Jameson can be found here.