— born in Indiana, either Decatur Co., IN, or Rush Co., IN:
4.  James Thomas ROBERTS, b. 4 Oct 1833 or 1831/2 {18, IN}
5.  William M. ROBERTS, b. 5 Jun 1835 or 1833/4 {16, IN}; d. 27 Aug 1907, Indianola, Warren Co., IA; m. 1856, IA, Cynthia Ann BILLINGS (b. 16 Jun 1839, IL; d. 12 Oct 1912, Indianola, Warren Co., IA)
6.  Susannah ROBERTS, b. 1837/8 {12, IN}
7.  America Frances ROBERTS, b. 1 Mar 1841 or 1838/9, IN {11, IN}

If the children's birthdates are from a family bible, they are undoubtedly more accurate than the 1850 census; whereas, if the birthdates are from tombstones, they are likely to be less accurate than the census because the person ordering the tombstone is usually either the spouse or a child of the deceased, neither of whom have first-hand knowledge of the birthdate of the deceased.

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

___, James

Blunt, Delila

Nov 18, 1824

Nicholas Co.

2.  1830 Census Index/Images (online at Ancestry.com; Image #15 of 67; extracted by Diana Gale Matthiesen):

1830

IN

Decatur Co.

Roll M19_26

p. 384

Ln. 7

Roberts James

200 010 - 100 010

These data indicate:

No. & Sex	Age Class	Therefore Born	Individuals Inferred
2 males	4 or under	1825-1830	= David (b. 1829) = John (b. 1827)
1 male	20-29	1800-1810	= James (b. 1804)
1 female	4 or under	1825-1830	= Sarah (b. 1825)
1 female	20-29	1800-1810	= Delilah (b. 1800)

3.  1840 Census Index/Images (online at Ancestry.com, Image #20-21 of 25; extracted by Diana Gale Matthiesen):

1840

IN

Rush Co.

Rushville Twp.

Roll M704_93

pp. 186B-187A/367-368

Ln. 4

James Roberts

112 001 - 200 100 100

0100000

These data indicate:

No. & Sex	Age Class	Therefore Born	Individuals Inferred
1 male	4 or under	1835-1840	= William (b. 1835)
1 male	5-9	1830-1835	= James (b. 1833)
2 males	10-14	1825-1830	= David (b. 1829) = John (b. 1827)
1 male	30-39	1800-1810	= James (b. 1804)
2 females	4 or under	1835-1840	= America (b. 1838/9) = Susannah (b. 1837/8)
1 female	15-19	1820-1825	= Sarah (b. 1825)
1 female	40-49	1790-1800	= Delilah (b. 1800)
1	person employed in agriculture

Listed next to James's father, Thomas ROBERTS (Ln 3, 010 000 001 - 000 030 001 | 0100000).

4.  1850 Census Index/Images (online at Ancestry.com; Image #35 of 204):  District No. 13, Wapello Co., IA, Roll M432_189, p. 417A, 232/232, enumerated 13 Sep 1850, official enumeration date 1 Jun 1850 (extracted by Diana Gale Matthiesen):

James Roberts	46	M		Farmer	1700	Ky
Delilah   "	49	F				"
David     "	23	M		Do		Ind
James     "	18	M		Do		"
William   "	16	M		Do		"
Susan     "	12	F				"
America F "	11	F				"

Listed next to son, John ROBERTS (æ 23, b. IN, wife Jane).

5.  Email from Jack W. Roberts.

My Great-grandfather, James M. Roberts b: 21 May 1804 married Delila Blount on 15 Nov 1824.  I have copies of the wedding bond and the statements by his father, Thomas Roberts and mother Susanna (Caldwell) Roberts attested to by a James H. Shankland.  Also a copy of the statement by Delila's mother, Athalia Blount, testifying that Delila was 21 years of age and giving her consent to the marriage, it also was attested to by James H. Shankland and dated 15 Nov 1824.  They were married in Nicholas Co., KY.

6.  Email from Dee Sardoch.  Supplied the children of our subjects.