Hello.
I've run into this family researching my own family and found the following book reference: Colonial Virginians and their Maryland relatives by Norma Tucker.

In this book, on page 87, Ms Tucker describes part of the Briscoe family as they pertain to the Tuckers.

She lists James Montgomery Briscoe as the father of the following:
Mason (who married Mary Wade)
Andrew
John
Margaret
Elizabeth
Samuel Montgomery (who married Elizabeth Barnes)
Emily Elliott (who married George Briscoe)
William P
Clarissa Jane (who married Henry Faulk Shaifer).

She shows James Montgomery Briscoe as being the son of Capt William Briscoe and his wife, Elizabeth Wallace. And, Capt William as being the son of Robert Briscoe.