— born in Fayette Co, TN:
6.  Harris F. ALEXANDER, b. 1841/2
7.  Mildred Clark ALEXANDER, b. 24 Aug 1844

1.  LDS.  Family Search: Internet Genealogy Service:  IGI - International Genealogical Index (online at FamilySearch.org).

Uriah ALEXANDER Spouse: Nancy QUERY Marriage: 18 Jan 1804, Cabarrus, North Carolina Source: An Index to Marriage Bonds Filed in the North Carolina State Archives

Moses Mc ALEXANDER Spouse: Margaret M. BOALES Marriage: 24 Jul 1830, Mecklenburg, North Carolina Source: An Index to Marriage Bonds Filed in the North Carolina State Archives

Mildred Clark ALEXANDER Birth: 27 Aug 1844, Gibson, Tennessee Father: Moses ALEXANDER; Mother: Margaret Source: patron submission

2.  1840 Census Index/Images (online at Ancestry.com, Image #107-108 of 118; extracted by Diana Gale Matthiesen):

1840

TN

Fayette Co.

Civil District No. 14

Roll 521

pp. 160B-161A

Ln. 16

Moses M Alexander

111 001 - 111 001 *00

no slaves

0100000

*It looks like someone put a "1" in the column, then went back and changed it to "0."
These data indicate:

No. & Sex	Age Class	Therefore Born	Individuals Inferred
1 male	4 or under	1835-1840	= Uriah (b. 1840/1)
1 male	5-9	1830-1835	= Thomas (b. 1835/6)
1 male	10-14	1825-1830	= ?
1 male	30-39	1800-1810	= Moses (b. 1808/9)
1 female	4 or under	1835-1840	= Narcissa (b. 1836/7)
1 female	5-9	1830-1835	= Mary (b. 1833/4) = Eleanor (b. 1831/2)
1 female	10-14	1825-1830	= ?
1 female	30-39	1800-1810	= Mary Margaret (b. 1804/5)
1	person employed in agriculture

The fit isn't perfect, and the older children, plus the fact that Mary Margaret is several years older than Moses, make me wonder if Mary Margaret didn't have an earlier Marriage.  She was certainly old enough to be the mother of two children born before 1830.

3.  1850 Census Every-Name-Index/Images (online at Ancestry.com, Image #18 of 30 — indexed "Moses Mcalexander"):  Civil District No. 12, Fayette Co., TN, Roll M432_877, p. 681B, 1490/1490, enumerated 26 Nov 1850, official enumeration date 1 Jun 1850 (extracted by Diana Gale Matthiesen):

Moses Mc Alexander	41	M		Farmer	2100	NC
Margaret      "	45	F				"
Elenor        "	18	F				"
Mary A        "	16	F				"
Thomas "      "	15	M				"
Narcessa A    "	13	F				Tenn
Euriah        "	10	M				"
Harris F      "	8	M				"
Mildred C     "	6	F				"
McCamey C Alexander	30	M		Farmer		NC?

Listed four households from Moses's parents, "Eureah" [Uriah] ALEXANDER (æ 70, b. NC) and his wife Nancy (æ 65, b. NC).

4.  1860 Census Every-Name-Index/Images (online at Ancestry.com, Image #8 of 8):  Holly Springs & Mt. Pleasant P.O., Township 2 Range 3, Marshall Co., MS, Roll M653_587, p. 116, PN 56, 376/370, enumerated 1 Sep 1860, official enumeration date 1 Jun 1860 (extracted by Diana Gale Matthiesen):

M C Alexander	50	M		Farmer		12000	N C
Mary Alexander	56	F					"
Thos W    Do	24	M		Farmer			"
Uriah     Do	19	M					"
Harris    Do	18	M					Tenn
Mildred C Do	15	F					Tenn

5.  1870 Census Every-Name-Index/Images (online at Ancestry.com, Image #64 of 74):  Byhalia P.O., Range Four, Marshall Co., MS, Roll M593_740, p. 678B, PN 64, 530/528, enumerated 1 Sep 1870, official enumeration date 1 Jun 1870 (extracted by Diana Gale Matthiesen):

Alexander M C	65	M	W	Farmer			North Carolina
_________ Margaret	65	F	W	Keeping House			N     Carolina
_________ T W	35	M	W	Farmer	1775	1290	N     Carolina
_________ Margaret C	28	F	W	Keeping House			N     Carolina
_________ Ada	4	F	W				Miss
_________ Robert H	1	M	W				Miss
Strube Cunigan	21	M	W				Miss
Strickland Jane	34	F	B	Domestic Sr'vt			South Carolina
__________ William	12	M	B				Miss
__________ Dosia	3	F	B				Miss

6.  1880 Census Every-Name-Index/Images (online at Ancestry.com):  not found.

7.  Archives of the ALEXANDER-L Mailing List (online at RootsWeb.com):  a message there says McCamey is McCamey Clark ALEXANDER.

8.  Messages posted to the Alexander Family Genealogy Forum (online at GenForum.com).

9.  WorldConnect / Ancestry World Trees (online at RootsWeb.com/Ancestry.com).