More than 1 possible:
The favoured by the fact Jacob names his first two sons John is:
Mary HARDCASTLE Cill Croft 18 Aug 1745 daughter of Jno HARDCASTLE, age in 1776 would be 31
2nd choice is:
Mary HARDCASTLE Fell Beck 25 Aug 1751 daughter of Rob HARDCASTLE, age in 1776 would be 25
3rd choice is:
Mary Hardcastle buried in Hampsthwaite 5 May 1767 daughter of William HARDCASTLE a Shoemaker of Darley. - Possible baptism 11 Dec 1749 daughter of Wm HARDCASTLE of Banks age in 1776 would be 27.