Saw your post on Simmons/Simons Family and have some information on this one as have them also linked to the Nettles/Harrell Family in Bertie Co and Chowen Co NC down into Anson Co Nc and on into SC and GA possibly LA and MS.
Silas left a will in Charleston SC indicating he was from St John Parish in South Carolina and it was dated 1795 (naming all the names in this but Jacob Harrell, Hester Simmons, and Ann Simmons in his will) so he died within this year as file and prove dates same year. Seems Selah was wed to a Nettles and had minor step-children when she came to wed Silas between 1787 and 1795, and thus would have two girls by him Anna Simmons and Hester Simmons that would wed their step-brothers Anna to James Nettles and they had son George Nettles, and Hester to Joseph Nettles, Jr.
Selah Harrell is the daughter of Jacob Harrell who's will was filed and proved in 1787 (naming three Simmons in it Selah, Ann, Silas) and is also on file today in Charleston SC Jacob was from St James Goose Creek Parish in SC.. Believe he tracks back with Jacob to Bertie & Chowen Co NC and over into old Nansemond Co VA. Also have hints that they may have come down from PA but still working on this..