I know that this is probably no help, but there is a Martha Cloud in the 1870 census. Information is as follows: She is living with Nathan Mitche, age 50, born TN (he seems to have a bunch of his own kids before Martha is listed. It is on page 2 of McDonald Cty, MO, Elk Township, Pineville Post Office. Martha is 8 years old born in MO. Also polled after her is Joanna Cloud, age 5 born in MO. In quering the 1870 census for Cloud's in that same county and township, there appears to be only one adult (page 1) with family (just incase someone was babysitting for Martha at the Mitche household when census was taken): Alexander Cloud, age 43, born TN; Martha, age 32, born IL; Willam, 12, born MO; Henry 10, born MO; Ida, 8, born ARK; Thomas, 4, born MO; Mary, 2, born MO. Doesn't seem that the Martha on page 2 could belong to this family, since they have a daughter, Ida, age 8, born in ARK; although it is interesting that the wife of this family is named Martha also. Lura