Seeking confirmation that Wm. Davison is grandson of Mary Garvin. Here's the pioneer trail I've been following:

Fairfield Co, Ohio marriages:
Mary Garvin married James L. Davis in Oct 1816
Nancy Hopwood married David Garvin in Aug 1820
Eliz Garvin married Ira(?Aaron) Powell in Jul 1826
Nancy Davis (probably b. Aug 1816) married John Balsley on 29 Dec 1833

Federal Land Office sales in Kosciusko Co, Indiana:
22 May 1835 Moses Powell
29 May 1835 Andrew Garvin
01 Jun 1835 Aaron Powell, next to Andrew Garvin
22 Sep 1835 Moses Powell
22 Sep 1835 David Garvin
18 Jan 1836 David Garvin
18 Jan 1836 James Garvin, next to David Garvin
21 Jul 1836 John Balsley
21 Jul 1836 James Garvin, adding
10 Oct 1836 John Balsley, adding
13 Jun 1840 James L. Davis, next to David Garvin
26 Jun 1840 James L. Davis, next to John Balsley

1840 Census Kosciusko Co, Indiana:
James L. Davis had a son age 20<30, possibly Samuel Davis b. 26 Sep 1820, m. 25 Nov 1842 Nancy Jeffries
a daughter 10<15, possibly Lydia Davis b. 1827, m. 23 Mar 1845 Henry Kimes, neighbor of David Garvin and James L. Davis
a daughter 15<20, possibly Eliza Jane Davis b. 1823, m. 3 Nov 1842 Joseph Kimes, neighbor of Andrew Davis and John Balsley
a female 70<80, possibly Nancy (McClain) Garvin

1850 Census Kosciusko Co, Indiana:
3 Aug, p.305a Mary (Garvin) Davis was 57
27 Jul, p.297a David Garvin was 51
11 Oct, p.385a James Garvin was 41
31 Jul, p.301b Nancy (Davis) Balsley was 33
31 Jul, p.301b Amanda Davis was 13 (Mary's daughter)

1853 John Balsley bought a next-door 40 acre parcel for $300 from James L. Davis
Amanda Davis m. 29 Jan 1854 William Davison. She d. 7 Jan 1857, age 20y-0m-16d, probably of childbirth complications.

1860 Census Kosciusko Co, Indiana:
15 Aug, p.xxx David Garvin was 60
31 Jul, p.xxx James Garvin was 49
6 Sep, p.169 Nancy (Davis) Balsley was 44
6 Sep, p.169 William Davison was 3 (Amanda's son)
6 Sep, p.169 Lucinda Davis was 14 (Mary's daughter)

John Balsley's 1871 probated will identifies nephew William Davison as an heir. The conclusion I have reached is that Amanda (Davis) Davison and Nancy (Davis) Balsley are sisters, because Nancy is the first child of James L. Davis and Mary (Garvin) Davis.

1879 atlas map identifies Wm. Davison owning land previously owned by John Balsley and originally purchased by James L. Davis. I believe that this 22 year old farmer is a grandson of Mary (Garvin) Davis