I saw your post and could this possibly be connected to your Eli Cooper married to Martha MNU..I have found other info in the census for the family. One of these children is related to my 2nd husband's family. Sarah Jane Cooper born in Camilla Mitchell Co Georgia. she is only listed as Jane in this census. I have only found one other Robertus Cooper which is yours and the dates are close. The Jack in this census may be John Wright Cooper since their BD is the same:

CENSUS YR: 1860 TERRITORY: GA COUNTY: Mitchell DIVISION: Gum Pond P.O. REEL NO: M653-131 PAGE NO: 58
REFERENCE: Enum. Date: July 12, 1860; Asst. Marshall: Jos. J. Bradford
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LN HN FN LAST NAME FIRST NAME AGE SEX RACE OCCUP. REAL VAL. PERS VAL. BIRTHPLACE MRD. SCH. R/W DDB
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REMARKS: Page 691 on microfilm.

3 403 409 Cooper Eli 35 M Farming 500 Ga X
4 403 409 Cooper Martha 30 F Ga X
5 403 409 Cooper Emily 13 F Ga
6 403 409 Cooper Anna 11 F Ga
7 403 409 Cooper Robertus 9 M Ga
8 403 409 Cooper Jack 6 M Ga
9 403 409 Cooper Jane 4 M Ga
REMARKS: Sex of this child is probably female.
10 403 409 Cooper William 2 M Ga
11 403 409 Cooper Missouri 1 F