Notes:
Data source is the 1990 book, "Moomaw-Mumma-Mumaw-Mumaugh Genealogy" compiled by Robert Austin Moomaw (deceased). .
Researcher is Doug Mumma, doug@mumma.org
1850 Census, IL, Pike Co,
Elizabeth Moomaw, 51, $600 real estate, b. Va
Sarah Nichols, 18, b. OH
Jacob Moomaw, 16, farmer, b: OH
Elizabeth " , 13, b. OH
May M. " , 10, b. OH
Charlotte " , 7, b. OH
Armilia " , 19, b. IL
Henry " , 1, b. IL
George W., 1/12
Illinois Statewide Marriage Index, 1763?1900
Groom Bride Date Vol./Page License No. County
MOOMAW, JACOB to HOOVER, LUCY ANN MRS on 2/02/1857 PIKE County
A little more looking and I found Lucy's first marriage
Illinois Statewide Marriage Index, 1763?1900
Groom Bride Date Vol./Page License No. County
HOOVER, DANIEL to HANKS, LUCY ANN on 12/01/1853 I/ 195 PIKE COUNTY
So, we know her marriage to Daniel Hoover only lasted a little over 3 years. No idea of her age. From his death date, we also know they were only married for 7-8 years.
We don't know if he was married earlier, but probably not. I looked for a later marriage for her and got lucky. She did remarry in 1867 a couple of years after Jacob died, which is not surprising. No wonder I could not find her in the 1870 census either.
Illinois Statewide Marriage Index, 1763?1900
Groom Bride Date Vol./Page License No. County
MURPHY, MARCUS L to MOOMAW, LUCY A on 09/27/1867 A /134 171 PIKE COUNTY
So, I will speculate that Marion was the son of Jacob Moomaw and Lucy Hanks Hoover. He would have only been about 5 years old when Jacob died and 17 years old when his mother diied.