The ravine on the San Hieronymo Peninsula was a narrow canyon located to the west of the silo and the power substation, on the east side of the peninsula. There was only one building in the entire area, directly overlooking the ravine, which appeared to be a small communications base, given the nature of the equipment inside as well as having a radio tower near the building. Caverns were also found within the walls of the ravine, some of which also reached two stories. Rockslides were also known to occur, which sometimes blocked the various thin pathways with large debris, forcing personnel to take an alternative route. In addition, to make patrolling the ravine more safe, wooden bridges were also placed between various edges.