It is the right height for sitting...

What was the purpose of all the work? What were walls on top of a ridge for?

The sides of the mesa were so steep, the walls weren't needed for defense. My silver truck can be seen below. This is where we climbed up, just left of that cleared slide or 'drag chute' where supplies may have been pulled up?.

At the top of the mesa Elizabeth found this metate (grinding stone).

Clam and oyster shells were all over the ground, inside the rock-cleared circles, on top of the mesa.