Looking for Burial Sites of Jonathan Case and Maria Cox Case from PA Who Lived IN Roscoe Illinois IN 1850 and 1860

Jonathan and Maria Case are my ggg grandparents. one of their children, Harriet Sybella Case is my gg grandmother. She had a daughter Flora Davis, m g grandmother who had a daughter Dora Katherine Zugenbuhler Elliott Farr, my grandmother. Jonathan Case was born in NJ and moved to Catawissa Columbia PA when he was a toddler. We have found everyone except his wife Maria....who could be Sarah Mariah Cox - we think she may be native American. They had six children. Sarah, Charles, Martha, George, Harriet, and William. Harriet remarried a Jonathan Westgate and they moved to Camanche, Iowa.