While reading your post, I came to remember vaguely about stumbling upon an old newspaper article from the 1850's featuring a Mr. Sompayrac's voyage to the West and his hostile encounter with Native Indians. I think I have this copy. I'm not related to the Sompayrac, but I suspect that my ancestor J. Delphin might have known him from Natchitoches. I just discovered that article when I was researching on the Delphin.

Donald