Mr.Kiel's book, page 64, footnote 100, cites a wedding invitation for May Gibbons, daughter of Mr. and Mrs. J.V. Gibbons and Adrian T. Stewart. The wedding was to be on Thursday morning, July 15, 1880, at 6 1/2 o'clock. (His source is Mrs Faustine Greene, Mount Union, PA, 1970).
Iowa Marriages at familysearch.org says the date was July 10. That might be the date of the license. Familysearch does that sometimes.
But I cannot find this couple together anywhere after that. Did they marry? Adrian T Stewart seems to be with someone else on later records who consistently says she was born in Nebraska.