In 1779 she married John Valance/Vallance in Cuckfield
Bit of a messy register, banns and marriages combined - not unusual then, but everything is handwritten.
Banns of marriage between Jno Valance of ye Parish of Worth and Piercy Smith of ye Parish
Then banns for three other couples
Then the marriage of John and Piercy
The mark of X Jno Valance
The mark of X Piercy Valance late Smith
https://www.familysearch.org/ark:/61903/3:1:S3HT-XC7S-J4GIt seems to be the same for all the brides around this time, even the few who signed did so with their married name and then their maiden/previous name is added afterwards, by themselves or otherwise.
Unusual?
The first marriage on that page was witnessed by another Piercy! Piercy Renvill. Thomas Renvill was the other witness, both marked.
So there were a few Piercys about!