There is a Mosby family Bible, 1765-1896, in the Va. State Library. It lists as children to Mary Woodson/Poindexter mosby, Clarissa and Daniel, and lists marriage for Clarissa to Hugh French and a son for Daniel Mosby -- John H., born 14 Jan 1765. Now, I wrote those down a long time ago, and they aren't my direct line. It's Poindexter's (b. 1725, son of Benjamin Mosby & Mary Ann Poindexter) sister Mary Ann Mosby who is my direct line. It's entirely possible that there was more in the Bible that I either couldn't read or didn't take the time to document. Spring is looking awfully busy for me, but if you don't have any luck checking with the library, I might have some time towards the end of June. The library has had to cut back a lot of staff, so I don't know what they're doing right now about copying and mailing things like this.
Let me know later if I can help.