1.  Family Group Sheet prepared by Betty Ann (Matthiesen) Cogliati and her grandmother, Maude Irene (Thompson) Rose.

2.  Jordan R. Dodd, ed.  1994.  Missouri Marriages: Early to 1850. Liahona Res., Orem, UT (Broderbund CD-227):

Markwood, Robert

Mccray, L.

1 Apr 1849

Grundy Co.

My guess is the "L." is a transcription error.  The 1860 Census should confirm the identity of his wife.

3.  1790-1870 Missouri Census Index (online at Ancestry.com):

1860

MARKWOOD

ROBERT

Grundy Co.

Washington Twp.

p. 456