I am looking through my information and will give some details that might be helpful others as well as Katie and Lundy so will post here.
The family Bible was left to Elizabeth MCROBERT, daughter of Rev. Archibald MCROBERT. She married Samuel CARTER 1 Jan 1798. I will have to go through more papers to see if I have anything on this CARTER line.
I am also going to check out the comments regarding a brother named Alexander as that information is not in my database. I have seen some information indicating there was an Alexander MCROBERTS who was in the same area as our ancestor.