I don't know anything further about Joseph Washburn son of Elisha Washburn Jr. I checked the online 1870 Michigan Census and did not see either Joseph or his wife listed. Though they both could have died and been buried I would think that odd since they really weren't that old. Have you tracked all of the children of Joseph Washburn to see where they went? Possibly Joseph or his widow went to live with a child in later life. Wish I could be of more help and I will keep my eyes open for this information Susan Bingler Fairfax, VA