Dear Ms. Pedersen,
Thank you for posting your request on History Hub!
To seek information on Doctor Francis Herriter Welty, we suggest that you begin by requesting his Official Personnel File (OPF). Once you receive his OPF, the Bureau of Indian Affairs locations will be listed. Then you may be able to determine which NARA unit holds that particular agency’s records here.
We hope this is helpful! Best of luck with your research!
[Information provided by Cody White, Subject Matter Expert]