I bought these four prints for two bucks each at a local thrift store. They are nicely mounted on 11x14 black matte board. A couple have captions and titles, but none are signed. It seems likely they were part of an exhibit.
The terrain visible in the last shot looks to me a lot like the country near Prewitt, New Mexico. There is a Navajo community there. However, the Laguna and Acoma Pueblos are near-by to the East and the Zuni Reservation is a short distance to the West of Prewitt. The subjects look pretty relaxed, which may indicate that the photographer was a member of the community.
I would like to know who the photographer was, and perhaps find some more of his/her work. I'm thinking that one possibility would be to visit the area and show around the pictures. Margaret and I have often visited the Chaco outlier ruins in this area, so we will probably get a chance to drive over there some time soon.