Mountaintop prayer seat?

I'm not sure if that's what it is, but it's picture #15 below. It just seemed so fragile, so precarious (in person). Here is a map of the area, with photo numbers and directions the photos were taken marked on the map:

The two small circles between the 8 and the 7 on the map are to mark a few rocks that were visible, but I can't be sure if they continued on to form a stone row. The snow was too deep to see a lot of detail.
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