Harvey, your Dougald Ferguson who married Elizabeth Archer immigrated from Greenock Scotland September 18, 1783. He had 4 brothers...Archibald, Niven, David and John and a sister Jenny. My mother is a Ferguson and still lives in Greenock Scotland.
I am spending the winter in California otherwise I could send you the whole family tree. Please contact me and I will send you the info when I return to Ohio in early April