She is daughter of Walter T. Colquitt with third wife Harriett Ross, they supposedly married January 10, 1842 near Macon she is said to have died about 1889 in/near Anniston, AL. This child is found, age 2 months, in their 1850 census household in Columbus, GA. If age reported was as of Census Day (June 1, 1850), she was born about March. But if it was as of Enumeration Day (November 22, 1850 in this case) then she was born about August.

"Columbus, Geo., from its Selection as a 'Trading Town' in 1827, to its Partial Destruction by Wilson's Raid in 1865," compiled by John H. Martin, Volume II (pub. 1875), page 54, shows from the Sexton's Report of Deaths that a child of W. T. Colquitt died aged 1 year -- death date or burial date (or both) is May 25, 1851. Same appears in "Columbus, Georgia: Lists of People in the Town, 1828-1852, and Sexton's Reports to 1866," extracted and arranged by Mary Jane Galer (pub. 2000), page 191 but cause of death unknown.

Mary Ann's father, who died May 7, 1855, is reported to be buried in Linwood Cemetery but the location of his grave is not known. His 2nd wife, Aphia Bushrod (Todd) Fauntleroy, reportedly died Jan. 23, 1841 in Columbus; they had just married there on December 10, 1840. There's a good chance she is buried at Linwood. If she is, and if Walter and this child Mary Ann are buried near Aphia, then these graves would all be in the Old Cemetery area. This part is guesswork. Also, not sure why they aren't marked because Walter was a wealthy lawyer and had been a Congressman.

UPDATE from : "While there is no record that explicitly states Walter Colquitt is buried in Linwood, the newspaper does report he was to be buried in Columbus, so Linwood is the logical location. Colquitt’s grave is not identiably marked, so without a sexton record to give the location, we have to rely on hearsay. Office personnel report he is said to be in the lot just north of the Sommerkamp Lot, NE corner of South Street #3 & Magnolia Avenue, which is 1-195, so Colquitt should be in 1-196 (it was relayed by Linda Kennedy, longtime Executive Director of the Historic Linwood Foundation, to Jane Brady, the current Director, that the first Superior Court judge for the local area is interred in the lot just north of the Sommerkamp Lot, she in turn having relayed this to Administrative Assistant Callie McGinnis, and Callie to me). Also buried here in 1-196 is Mrs. Rebecca Penn (Grigg) Malone, buried September 25, 1883, age 75. We do not know who is in the one marked adult grave, as it bears no inscription, but probing indicates other graves that are covered over. One of those is quite likely the grave of Mary Ross Colquitt (died 1851). The list of lot owners for Section 1 does not include Lot 196. This section was laid out and put into use around 1845."