Martha Glenn in Saline County, AR

Hi folks. I'm seeking additional information about Martha Glenn, born 1842 in Saline County, AR. We believe her parents were John Glenn & wife Malinda Crawford. (Note: This can be confusing, because John Glenn's brother William married Malinda's sister Lydia--and Williams and Lydia also had a daughter they named Martha. But that Martha is written as "Martha R" in census records, whereas our Martha has never shown a middle name or initial.) Our Martha Glenn married Dr. Robert Morrow Russell in Saline County, AR in 1867, and they moved to Johnson County, TX in 1874. I would love to find additional information about Martha and Robert during their time in Saline County (between 1867 and 1874). Also I would love to find additional documentation/corroboration that our Martha Glenn is indeed the daughter of John Glenn and Malinda Crawford. Thanks very much for any and all help.