Found this with a Francis M in it but the birth years are way out. https://www.familysearch.org/ark:/61903/1:1:M65S-F8Q?lang=en
A George Washington Davis and a Francis M in the same family, but as you said Francis' birth is way off - he was married for at least a year or so by 1850.
How is that the case, My DOB for Mary Collier is 1845 she would have only have been 4 when he married her in that case! Something is wrong here.
Sorry, I meant 1860.
1860 Township 18 N Range 13 E, Pemiscot County, Missouri
P.O. Caruthersville
July 13, 1860
Page 39, family 289
Francis M Davis, age not known, levee builder, personal estate: $200, born in Kentucky
Josephine Davis, age not known, housewife, born in Missouri
Alex Devlin [Doolin], age not known, female, no occupation, real estate: 200, born in Missouri
William H Davis, 1, born in Missouri