Desperately seeking Susanna

I am looking for any information concerning the final resting place of Charles W. Cooper born June 1846 and Susannah J. Queen born May 1844. They were married in Pomeroy, Meigs County, Ohio on March 6, 1866 and lived in Belleview, in either Washington or Iron County, MO in 1900 per Census index # 112-131-4-70 Belleview is near the county line so it is hard to tell where.

On January 30, 1903, their daughter Arminta Cooper married John William Lucas in Irondale, Washington county, MO. After that, it appears they disappeared. Any information on Charles and Susannah would be greatly appreciated.