Some secondary sources have Nancy also married 2nd to "Mr. JONES" and 3rd to "Asbury HARPENDING."  See sources below for the reason these additional marriages are incorrect — aside from the fact that Beverley outlived Nancy, so he was the one widowed and remarried, not she.

A number of secondary sources give Isabella's surname as HENSON, but if you look at the marriage records of Pope Co., IL, not only is her surname HENLEY, there are numerous other HENLEY marriages and no HENSON marriages.  Also, in the 1840 Census of Pope Co., IL, there were two HENLEY families (Abner and John), but no HENSON families.

Most secondary sources attribute Zarilda to Isabella, but please note that Zarilda was not only born before Beverley married Isabella, more importantly, Zarilda was born in Kentucky.  So, even if Zarilda's age in the census were wrong, I'd find it hard to believe that Beverley went to IL, married Isabella in 1839, came back to KY where she birthed Zarilda, then they went back to IL to be in the 1840 census, then went to TN by 1841/2 to birth James.  It makes far more sense that Zarilda was the last child with Nancy, in KY, before he went to IL and married Isabella, then went to TN.  Montgomery Co. is just over the state line from Christian and Todd Cos.  (Nancy's parents were married in Montgomery Co., but lived in Christian Co.)  There are strong ties between many families in Christian/Todd Cos, KY, and Montgomery Co., TN, due to the natural geography — with the West Fork of the Red River flowing south to meet the Red River just before its confluence with the Cumberland River at Clarksville — irrespective of the political boundaries.

1a.  Jordan R. Dodd, ed.  1993.  Kentucky Marriages:  Early to 1850.  Liahona Research, Orem, UT (Broderbund CD-229):

Stubblefield, Beverly

Clark, Nancy Wright

16 Jul 1823

Christian Co.

1b.  Anon.  1983/96.  Kentucky Marriage Records: from the Register of the Kentucky Historical Society.  Genealogical Publ. Co., Baltimore, MD (Broderbund CD-519):

p. 145

Stubblefield, Beverly Clark, Nancy Wright....July 16, 1823    Strother Smith

Strother SMITH was Nancy's brother-in-law (husband of her sister, Susan).  Beverly had been his security when Strother & Susan married two months earlier. 

1c.  Jordan R. Dodd, ed.  1993.  Illinois Marriages:  Early to 1850.  Liahona Research, Orem, UT (Broderbund CD-228):

Stubblefield, Beverly

Henley, Isabella

11 Apr 1839

Pope Co.

2.  Census Index:  U.S. Selected Counties, 1830 (Broderbund CD-315):  no Beverly STUBBLEFIELD found, anywhere.  Based on this (incomplete and often inaccurate) CD, the only STUBBLEFIELDs in Kentucky were John in Todd Co. and Thomas in Logan Co.  Beverly did have a brother named John; perhaps they were living with him.  Beverly's mother was widowed by this point and, if the 1850 census is any indication, she was still living in Todd Co., so perhaps both John and Beverly (and other children) were living with her to care for her, with John coming up head-of-household.  The numbers will tell...

3.  Census Index:  U.S. Selected Counties, 1840 (Broderbund CD-316):

1840

Stubblefield, B.

IL

Pope Co.

p. 180

There are no other STUBBLEFIELDs in the county, but there are two HENLEYs:  Abner and John.  There are many HENSONs in Illinois, but none in Pope Co.

4.  1850 Census Index/Microfilm (online at GenealogyLibrary.com):  Montgomery Co., TN, p. 192A, 846/846, enumerated 9 Oct 1850 (extracted by Diana Gale Matthiesen):

Beverly Stubblefield	50	M	Carpenter		Virginia
Isabella        "	35	F			"
Zarilda         "	12	F			Ky
Wiliam H.H.     "	10	M			Illinois
James E.        "	8	M			Tenn
John J.         "	6	M			"
Benjamin W?     "	4	M			"
Mary            "	2	F			"
Haldu/Haidee A. "	1	F			"

5.  Jordan R. Dodd, ed.  1993.  Kentucky Marriages:  Early to 1850.  Liahona Research, Orem, UT (Broderbund CD-229):

Jones, David	Wicks, Nancy	19 Dec 1822	Christian Co.
Harpending, Asbury	Jones, Nancy W.	8 Aug 1835	Christian Co.

The Nancy W. JONES who married Asbury HARPENDING in 1835 was not a twice-widowed Nancy Wright (CLARK) STUBBLEFIELD JONES, but the once-widowed Nancy (WICKS) JONES.

6.  WorldConnect (online at RootsWeb.com).

7.  Message in the Stubblefield Family Genealogy Forum (online at GenForum.com).