I came down out of the forest on Sunday and walked/drive this military ghost town.
It was an actual Western cavalry fort, then an army tuberculosis hospital compound (biggest in the world at the time, 400 buildings), then VA then basically dismantled as a WPA project.
Found a button. Mother of pearl? Returned it to it’s hiding place:
Also found that looks like a bathroom tile:
Caught and released.
This appears to be a materials weathering test. The samples are numbered serially: