You could be right . The ones there have similar sorts of patterns and are about the same diameter. The only difference I can see is the edges are not as eroded. I noticed today that they are on two different stones , both earth fast and part of the natural formation. One is on the west side and the other on the east . The one on the west side also has a number of rock basins on it. These are formed by natural erosion from water and wind on the granite.

Peace , Lubin