I went back and checked on the stone axe head I found. Still there (not collected yet by the informed archaeologist). I did get an opinion from a local expert: "The axe you found is likely Pueblo I/Pueblo II (750-1150) associated with Pueblo groups who migrated from the north into the PEFO area. The convex shape in the middle is unusual and may mean it was originally something else or it allowed the haft to fit more comfortably."