States: South Carolina: Edgefield
It could be that this William Clark was born 1790 and married in Amite Co. Miss. to Elizabeth Isaacks who was born in 1798 (If correct he married her when she was 14 years old), in 1812. They had daughter Mary Clark who was b. 1820 and she married in 1840 in Sabine Co. Texas to a Hiram Donahoe (spelled also Danahoe, Donhoo, or Donahoo). I have tried to trace this William Clark without success. He may be the one who lived near Milam, Texas in Sabine Co.
This William Clark probably moved to Miss. with some of the Martins..
Sorry I can't be of more help.