I have had no luck in finding John the Elder on the 1870 census, but I keep looking!

The Galva historian sent me the following newspaper announcement from Thursday, November 29,1894. I assume it is from the Galva News but I don't know for sure.

"John Corkill, father of ex-supervisor J.J. Corkill, died at the home of his son east of town last Thursday. The funeral occurred Saturday at 1 P.M. from the house."

This would make John the elder's death date 22 Nov 1894 in Galva, Henry County, Illinois.