Ninetyone-Mile Canyon — Just east of Trinity, a safe route goes all the way to the beach, but there is not much opportunity except to go back up again. There may be water in the bed above or below the first fall. There are three significant scrambles and bypasses, all easily negotiated without a pack.

Routes — The Tonto connects between Utah Flats and Trinity and the ridge between Ninetyone and Trinity gives access to the track along the top of the Shinumo cliffs that leads to the Isis/Cheops saddle and access to Phantom Creek. One could go up the bed directly and pass up through the cliffs in the bay south of Isis; there is a huge semi-detached tower balanced along the rim on the east side, and a small ruin on a ledge on the opposite wall.

1996 December - Across Utah Flats and south of Cheops with a dayhike to the beach and back. Exploration of the mesa between Ninetyone and Trinity, another overnight and then back to Utah Flats along the terrace below Isis and collecting water in Phantom Creek. Four nights out.