After we lost the Bell Rock loop trail and had to backtrack, we found this spiral of rocks on a ledge on the west side of Bell Rock, apparently marking a vortex area. We can't say that we sensed anything, but there were two adjacent shallow depressions that sometimes hold water, and standing in these gave a strong sense of "grounding" (a sense of heaviness while in the spot, as though somehow more solidly connected to the earth).