My Foremans are way back in England and connect to Dogget and Lewis. But I'm responding to your post because there is a way to PROVE genetic relationships. First, are your Foremans direct line males? If so then take a test for the Y chromosome using the STR markers, Familytreedna.com As long as others of that line of Formans have tested then you can compare to see what lineage you are from.
But, if your line is from a female of the Foreman line then you can test for your Autosomal Chromosomes. You see, every ancestor you have leaves some signature of genetics in your autosomal chromosomes. It might or might not be measurable.
The price at 23andme is under a hundred and they do the medical part too. The data is awesome. It can help you find genetic cousins but you do need a good genealogy file to help you figure out HOW your related.
To help understand genetic testing I suggest you read this FREE page of data.http://geneticsand.us/
And go get tested