Joseph Slater is somewhat of a mystery man. Unlike many other members of the Ashley Rangers, I have been unable to find him listed in the 1860 census of Ashley or surrounding counties; nor in Arkansas Confederate pension records; nor in cemetery, marriage, or land patent records in southeastern Arkansas. All this leads me to surmise that he may have actually lived across the State line in Louisiana. There is one Slater family listed in the 1860 Ashley County census. According to his Arkansas pension application, Hugh Slater served in Co. B, 4th Louisiana Cavalry. I don't know if this information is useful to you, but here it is --

HH#120, Bearhouse Township

SLATER, Hugh, 33, m, Mississippi, farmer

N. J., 40, f, Mississippi

Clarissa M., 12, f, Mississippi

Julia A. E., 10, f, Mississippi

Eliza E ., 8, f, Mississippi

Marion M., 4, m, Arkansas

G. I., 3, m, Arkansas

Hugh, infant, m, Arkansas