CalTopo Export Export from CalTopo Chokestone An enormous chokestone blocking the passage between the middle and lower narrows is a great example of the power of previous flash floods. 300ft (90m) up canyon to take the clear bypass trail up the hill on the eastern wall past the chokestone then down to the canyon below into the lower and final set of narrows. -117.33533352613449,36.606868756674764,0