Here's what Charles Knighton (The Clay, Bruce & Kavanaugh Families) has:
RICHARD PRESTON2 BRUCE (John1), son of Capt. John and Elizabeth (Clay) Bruce, was also born circa 1780 in Virginia and died between July and October 1841 at his farm on Cabin Creek, near Washington, Mason County, Kentucky.
March 25, 1814, [deposition of Richard P. Bruce] he was married first to Mrs. Elizabeth “Betsy” (HENLEY) Bullitt (prob. b. ca. 1790), 25 Mar 1814, Jessamine County, Kentucky. She was a native of Virginia and a resident of Fayette County, Kentucky. [In his booklet, Family History of Sgt. John Bruce & Kin, printed in 1970, Marion N. Bruce surmised that Elizabeth may have had children by her first husband, Wilson Bullitt, but had found no evidence.]
Richard P. Bruce married secondly, Mrs. Sarah “Sallie” (HULTZMAN) Coffrin.
Richard Preston and Elizabeth (Bullitt) Henley Bruce [probable; one proven]:
i. female, b. ca. 1814/5 [1810-20]; alive 1830 [1815-20]; alive 1840
ii. male, b. ca. 1816/7 [1810-20]; alive 1830 [1815-20]; gone 1840
iii. male b. ca. 1818/20 [1810-20]; alive 1830 [1815-20] ; gone 1840
36+ iv. RICHARD PICKLE BRUCE, b. 15 May 1818[1810-20]; [1815-20]; [1810-1820]
Richard Preston and wife, Sarah (Hultzman) Coffrin-Bruce [as named in his will and as enumerated in 1840 census, Mason Co., Ky]:
37 i. HORATIO BRUCE, b. ca. 1833; residing with his mother in 1870
38 ii. SARAH J. BRUCE, b. ca. 1835-40
39 iii. ROBERT G. BRUCE, b. May 1839. Issue of Robert G. Bruce:
i. BRUNETTA BRUCE, b. ca 1872
ii. PATRICK N. BRUCE, b. ca 1874
iii. DOLLA BRUCE, b. ca 1876
iv. THOMAS BRUCE, b. July 1878 (“Buddy” on 1880 census)
v. ROBERT BRUCE, b. Oct. 1881
vi. DILLIE BRUCE, b. Aug. 1886
vii. MARY L. BRUCE, b. Aug. 1888
RICHARD PICKLE3 BRUCE (Richard Preston,2 John1), son of Richard Preston and Elizabeth (Henley)
Bullett Bruce, was born 15 May 1818 in Garrard County, Kentucky, and died 1 October 1909 at Winterset,
Douglas Township, Madison County, Iowa.
Richard Pickle Bruce was married 28 January 1841 in Brown County, Illinois, to Judith Amelia KEITH (b. 13 June
1821 Clark Co., Ky.; d. 16 June 1875 Winterset, Ia.), daughter of Peyton R. and Judith Amelia Keith. In 1884, he married secondly, Miss Elizabeth McCLARY.
Richard Pickle and Judith Amelia (Keith) Bruce:
126 i. JOHN BRUCE, b. ca. 1841 Il.; not found in 1860.
127+ ii. FRANCIS MARION BRUCE, b. 23 Oct. 1843
128 iii. MARY ANN BRUCE, b. ca. 1845/6
129 iv. GEORGE ANN BRUCE, b. ca. 1847/8
130 v. SUSAN V. BRUCE, b. ca. 1849/50
131 vi. ROBERT S. BRUCE, b. ca. 1852 Ia.
132 vii. CAROLINE M. BRUCE, b. ca. 1854
133 viii. MARTHA S. BRUCE, b. ca. 1856
134 ix. HENRIETTA BRUCE, b. ca. 1858
[1850 census Brown Co., Il., p. 155, reel 155; 1860 census Madison Co., Ia., Center Twp., p. 698]
You will note no Nancy Belle -- perhaps she was born after the 1850 census? Or, perhaps she was Georgie Ann?
Now that you mentioned this family, the 1870 census of Douglas, Madison, Iowa has Nancy B, age 8. I suppose this is your Nancy Belle?