Whether Fothergill and Sothergill are alternative spellings of the same family or the names of two completely different families is a question I have never resolved. It's reasonable to think that Sothergill and Smothergill are the same family (and there are data to support it). But Fothergill? That's a stretch and I have no findings to indicate they are related, but it is possible of course. The whole thing is complicated by the fact that way way back in England the letter S at the beginning of a word was made by an F.if you can find a connection between Sothergill and Fothergill in Canada I would be delighted. As you probably know, there were Sothergills in both Ontario and Quebec from about 1850 through the early 1900's. Good Luck!