Alfred Byrne Horner1 
Charles Gustavus Horner1 
Emeline Byrne Horner1 
From 6 January 1886, her married name became Belt.
Child of Emeline Byrne Horner and John Belt
- Mary Theresa Belt+2 b. 3 Apr 1893, d. 2 Mar 1973
John Belt1 
He lived at Beltsville, Maryland, U.S.A.G.1
Child of John Belt and Emeline Byrne Horner
- Mary Theresa Belt+2 b. 3 Apr 1893, d. 2 Mar 1973
Mary Theresa Belt1 
From 2 November 1917, her married name became McDonnell.
Children of Mary Theresa Belt and Major Austin McCarthy McDonnell
- Dr. John Chilton Horner McDonnell+2 b. 13 Oct 1920
- Austine Byrne McDonnell+2 b. 22 Nov 1928
Eugene McDonnell1
He lived at Doneraile, County Cork, IrelandG.1 He lived at Baltimore, Maryland, U.S.A.G.1
Child of Eugene McDonnell and Ann Chilton
- Major Austin McCarthy McDonnell+2 d. 10 Feb 1965
Major Austin McCarthy McDonnell1 
Children of Major Austin McCarthy McDonnell and Mary Theresa Belt
- Dr. John Chilton Horner McDonnell+2 b. 13 Oct 1920
- Austine Byrne McDonnell+2 b. 22 Nov 1928
Dr. John Chilton Horner McDonnell1
He was educated at Johns Hopkins University, Baltimore, Maryland, U.S.A.G.1 He graduated from Chicago Univeristy, Chicago, Illinois, U.S.A.G, with a Doctor of Philosophy (Ph.D.)1 He was a scientist with the U.S. Government, specialising in rocket fuel.1 He lived in 1976 at 107 Jenkins Drive, Indian Head, Maryland, U.S.A.G.1
Children of Dr. John Chilton Horner McDonnell and Beatrice Martin
- Mary Byrne McDonnell2 b. 28 May 1953
- Peter Martin McDonnell2 b. 28 Apr 1955
- Katherine Therese McDonnell2 b. 4 Dec 1961
- Barbara Ann McDonnell2 b. 4 Dec 1964
Beatrice Martin1
From 12 August 1952, her married name became McDonnell.
Children of Beatrice Martin and Dr. John Chilton Horner McDonnell
- Mary Byrne McDonnell2 b. 28 May 1953
- Peter Martin McDonnell2 b. 28 Apr 1955
- Katherine Therese McDonnell2 b. 4 Dec 1961
- Barbara Ann McDonnell2 b. 4 Dec 1964