I, too, have access to the Alexander Harry Davis book and did not think to look for the name "Harry" instead of Horry.I apologize.It appears he based their date of marriage upon the age of their first known child, not documented.As you probably are aware, Wm. C is mentioned on pages 15,71,134,162 and 203; also a Wm. Clyde is mentioned who was not the same person as Wm. C. Since her father(John Evan/Even Harry) married her mother in Cheraw Dist. S.C. and their first child, Evan Harry was bn 1765 S. C., I checked the Archives in S. C. and found that J. E. Harry is shown on a plat for 50 acres for Charles Rice.This was in the Georgetown District, in 1788, ~ check SC Formation of Counties Timeline. Then, Even Harry has a plat for 100 in Craven Co., in 1738 as well as another 100 acres in Craven Co, in 1743, etc. 1790 census shows a John Harry - Laurens Dist., S. C. 1790 census shows a Jonathan Harry - Orangeburg S., S. C. 1820 census shows a John Harry - Barnwell Dist., S. C. 1820 census shows a John Harry - Laurens Dist. S. C. Also, from SC Archives, Joseph Davis' Last Will and Testament of the Marion District; Mentioned Abraham G Davis, Benjamin S Davis, Daniel H Davis, Joseph Davis, Joseph J. Davis, Susan Davis -----William C. Davis----, James R. Ervin and a number of Africans. ( I think I've sent this info to you). In all of this checking, I have no results.Hope you have better luck!