I need help in locating parents for Robert S. Knox born abt 1815 in possibly Iowa, Ohio. He married Elizabeth Martin born abt 1824 in 1840 in Greene, Indiana. In 1850 he, Elizabeth, and children were in the 1850 Census of Ozark Co, MO. In 1860 this family was listed on that census in Collin Co,Texas, and he registered for the Civil War in Dallas in 1862.