Thanks for the reply. Another abstract of a will of Montgomery Co., MD: Sarah BRISCOE, pr. 6 Nov. 1799. Witnesses John CHAMBERS & John BELT. Codicil, 1 Jan. 1799, wit. John TUMBELL {sic}, Benj. RICKETTS, Marry {sic} HARRISON. Codicil mentioned Sarah's husband Robert BRISCOE. His will, pr. 28 May 1798, mentioned his wife's grandsons named CAISE, sons of Margaret CAISE, dau/o Sarah BRISCOE.

Have you found any BRISCOE connection?

I Googled the names and found that a John TURNBULL m. Sarah BELL {sic} & had Mary, Margaret, Elizabeth, Wm., & John. John TURNBULL, b. 27 Dec. 1780, m. 11 July 1801, Montgomery Co., MD, Mary TANNEHILL, dau/o Carlton TANNIHILL. I think John TURNBULL who m. Sarah was the one who died in 1813, and Sarah was actually Sarah BEALL, b. 1754, dau/o John BEALL, b. 1728, & Mary DENT, b. 1731. The 1801 marriage is verified by MANUEL's Montgomery Co. M. Licenses.

Never give up!