Hi Laurel, Thank you for replying. I indeed have that Andrew Mitchell's bible; his name and "1794" are engraved on the cover. I did not buy this Bible, but it came down in my family, and my mother recently gave it to me, along with other documents and items from Andrew's family.
The bible does not, unfortunately, contain the hoped-for lists of descendants, but it has some annotations by him and his wife, Margaret, who was originally Margaret Stites, a daughter of Dr. John Stites Jr. Some of the inscriptions are very moving, and indicate some of the hardships of their lives.
I have learned a great deal about Andrew Mitchell and his family since I posted my message. I know that Andrew Mitchell was an immigrant from Scotland before the Revolution--so not likely descended from Robert Mitchell.
As for Thorne Mitchell, were the names in that bible ever recorded?
As for me, to my knowledge I am not descended from Andrew Mitchell, but from his wife's sister, Maria Stites, who is related to Bowerings and Quicks. Andrew's line might have died out and the papers transferred from sister to sister (or cousin to cousin).