Thank you for those resources. I will look at them. Hopefully I will find something.
None of the people from the 1860 page with James and Elvira can be found in Grimes county in 1870. A whole page worth of people can't be missing, then show up again in 1880 as if they never left.
Elvira gave sworn testimony in her widow's pension in 1878, so she couldn't have died in the 1860s.
Her husband died in 1869, so he should be on the mortality schedule for the 1870 census.
Thank you for your help!