Hi Tricia,
As far as I can tell, John Madgett & Elizabeth Gibbon had about 8 children and I am descended from their son George who married Phoebe Cobb. If you PM me, I can share my info wth you. Likewise, I'd be interested to learn what you know. It's a shame that we can't get back further, especially when it's such an uncommon name, it ought to be easier!