Golgotha is cut into a ridge of basalt that is flung out from the base of the mountain—like a buttress root from the trunk of a jungle tree—that separates the watersheds of the Yamamoto and Tojo Rivers. Moving southwards from the summit of Calvary, then, one would pass through the teeming bowl of its extinct crater first, over the remains of its southern rim, and then onto the gradual downward slope of a much larger mountain on which Calvary’s cinder cone is just a blemish, like a wart on a nose. The small Yamamoto River runs generally parallel to the Tojo on the other side of the basalt ridge, but descends more gradually, so that its elevation gets higher and higher above that of the Tojo River as both work their way down the mountain. At the site of Lake Yamamoto, it is fifty meters above the Tojo. By drilling the connecting tunnel in a southeasterly direction rather than straight east underneath the ridge, one can bypass a chain of rapids and a waterfall on the Tojo which drop that river’s elevation to almost a hundred meters beneath the bottom of the lake.