The first point was to discover the entrance under the casing, which masked it.

It was nearly in the middle of the north face (fig.

136), but at the level of the eighteenth course, at about forty- five feet from the ground.

When the block which closed it was displaced, an inclined passage, 41.2 inches wide and 47.6 inches high, was revealed, the lower part of which was cut in the rock.

This descended for 317 feet, passed through an unfinished chamber, and ended sixty feet farther in a blind passage.