This is the wife of Daniel Scofield and Miles Merwin. We only know her as Sarah Unknown, but because of an association with the Youngs family, her maiden name is often-assumed to be Youngs.
We have no evidence for this. In fact, a recent (1998) article was written about the issue in NEHGS - saying we do not know her maiden name. I have created an Unknown profile for her and need to propose a merge.
This profile is often duplicated under all three names, Youngs, Scofield and Merwin (and by the spelling Merwyn). Please PPP