I have conflicting sources:  some that say Alexander died before 1850, leaving Mary Ann a widow; others say he divorced her.  Their daughter, Delilah, was a dwarf, which sadly, for some, could seem to be a justification for divorce.

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

2.  Jordan R. Dodd, ed.  1993.  Missouri Marriages:  Early to 1850.  Liahona Research, Orem, UT (Broderbund CD-227):

Ervin, Alexander

Thompson, Mary Ann

Jan 31, 1844

Grundy Co.

Apparently, this must be the bond date or license date, not the date of the ceremony.

5.  1850 Census Index/Microfilm (online at GenealogyLibrary.com).  The index on the CD says "Union Town," but the location field on pages 378A to 382A is blank.  The entries for Union Town end on p. 377B; the entries for "South Fork of the American River" begin on p. 382B, and every page before and after is labeled with the location.  The record reads:  El Dorado Co., CA, p. 378A, 6/6, enumerated 24 Oct 1850 (extracted by Diana Gale Matthiesen).  In the margin, to the left it says, "Hotel."

Thomas Thompson	48	M	Hotel	4200	Ky
Mildred    "	43	F			"
Isaac D.   "	33	M	Physician		"
Mary A     "	21	F		150	Mo
[five siblings]
[seven lodgers]

Mary Ann (THOMPSON) ERVIN is a widow (or divorced) at this point, so why is she called Mary A. THOMPSON?  And where is her daughter, Delilah?

2.  John C. Spickard.  [1987.]  "Bible Records:  Family Bible of Roy & Maude Spickard." Grundy Gleanings (Grundy County Genealogical Society, Trenton, MO) 3(3): 4. Family bible of George Alexander SPICKARD & Mary Ann THOMPSON.

3.  John C. Spickard.  1990.  "Delilah Ervin Dunham." Grundy Gleanings (Grundy County Genealogical Society, Trenton, MO) 6(4): 1+3. Biographical sketch of subject, with image. 

4.  "Death Notices:  Mary A. Thompson Spickard." Grundy County Gazette, Grundy Co., MO.