I came across this odd boulder in a stream that runs beside a fairly busy rural road. There are a number of pull-outs along the road that seem to have been cleared for fishermen who park there in droves during the 'season'. The stream is quite rocky in a lot of places, and I walked with great difficulty on a bed of medium sized stones that brought me to this formation. I haven't a clue to how the pool in the rock was formed except for the possibility that it was the result of a chunk that may have broken out of the larger host boulder. I suppose eons of freeze and thaw would do that, but it's cool to see however it came to be.