Furnace Flats — This informal name is given to the slopes on the north side of the river between Basalt and Unkar Creeks.

Routes — It is just possible to travel the riverbank from Unkar Delta most of the way to Basalt. The bank immediately above Unkar is well-traveled with several small river camps. At the lower end of the island above Unkar is a cliff that can be waded at moderate flow. The area just above this is restricted (Mile 72).

Just below Basalt the bank is impassable, although some have done it at low water. There are no obstacles higher on the slope where an Anasazi track connects with Basalt Canyon.

1998 May - Bright Angel to Saddle Mountain North Rim Passage: day 6.