I have found (thanks to a generous fellow researcher) that my previous posting had some errors.
John G. Niblock's parents were William Niblock and Louisa. Both born in Ireland. John was born in 1848 in Pennsylvania and died 7 April 1914 in Iowa. He married Medora Clark born 1858 died 28 Dec. 1909 in Iowa.
I would appreciate hearing from anyone else researching this family,