The Angus administrator was kind enough to inform me that Forfashire and Angus are one and the same. I have done a bit more research and found that our Jamiesons (Thomas Jamieson born abt 1786) came from the town of Inverkeilor and his wife (Mary Farquhar born about 1786) came from Maryton and died in Friockheim, Kirkden. Two of their children were born in Kirkden: Margaret Jamieson and Agnus Jamieson. Three were born in Inverkeilor: John Jamieson, Thomas Jamieson and James Jamieson.
Grandsons James J Jamieson, Thomas, and Joseph were all born in Arbroath. Several siblings were born in Nord-Pas-de-Calais, France, as their father James Jamieson went there for work. He was a machinist who designed looms. Hope these details might be familiar to someone. Thank you!