I've found a Hannah Fox on findagrave that married a Captain Samuel Gilbert but she was born in 1761, not 1740[[http://www.findagrave.com/cgi-bin/fg.cgi?page=gr&GRid=86505500]]. Their marriage took place in Vermont, not Pennsylvania. She certainly couldn't have married a Samuel Gilbert who was over 150 years older than she was.
Possible wife for the Samuel Gilbert who settled in Pennsylvania is Susannah Rush.
If Fox-7699 is the Hannah Fox who married Captain Samuel Gilbert in Vermont, her birth year is 1761, not 1740. If she's not, then which Samuel Gilbert did she marry?