Ed,
That looks like quite a big brick wall. The name "Nohearn" does not
sound german to me at all. As you probably know, names were changed many
times when people arrived in the states. Especially when they had names
that were not easy to remember or even write. I tried to find german
names that could sound like "Nohearn". I did not find any. The only name
I can think of is "Nöhring" (Noehring). So I would suggest to look for
names that could sound like Nohearn or that have similar spelling.
Good luck
Wolfgang