I'm a wee bit late to this party, but are you aware of any connections between your Johnstons and those of Prescott Co.? As I recall our Archibald Johnston married a Peggy Gordon. Is she yours?
Here's a link to my Johnston Family Album on PBase: http://www.pbase.com/cjmax/johnston_family_album&page=al...
Clifford "Cliff." Johnston