Pierpont Antique Watch in original case

This counfounds me. I found it in my mother's jewelry box, but I never saw her wear it when she was alive. I cannot find something like it anywhere. The band is sort of spring-loaded, i.e., there is no clasp. It seems to be gold, and a decco design. I have searched everywhere to find something about the company (I don't think it still exists) and what the age might be. I would be thrilled if someone had an idea what I hold here...trash or treasure?