Re: Thomas Jefferson Merritt, b. 1851
Don't know who John Rand's parents are, yet. However, we now have three lines of these Merritts related by DNA. They include John Rand, Samuel Merritt of Botetourt and Jesse Merritt of NC. Maybe working back through the related families, you will find their common ancestor.
You can see them at this page, just seach on John Rand to find it, Lineave IV.