Hance Rapids is the first challenging white water that river runners [1] encounter—a preview of things to come as the river enters the narrower confines of the Inner Gorge, or, as explorer John Wesley Powell called it, the Granite Gorge:
Heretofore hard rocks have given us bad river; soft rocks, smooth water; and a serious of rocks harder than any we have experienced sets in. The river enters the gneiss! We can see but a little way into the granite gorge, but it looks threatening.
Just past Hance Rapids, the oldest rock in the canyon, pink and red Zoroaster granite and dark gray Vishnu schist, appears. These harder rocks form steep cliffs below the Tonto Platform [2], creating a canyon within a canyon. In the Lower Sonoran Desert climate zone, summer temperatures can push toward 120°F, and even lizards take cover in midday.
Cremation Camp, a popular overnight for river runners at mile 87, appears stark and rocky at midday, but when late-afternoon sun hits the Zoroaster granite, the rocks seem to smolder with inner fire.
Links:
[1] http://www.moon.com/destinations/grand-canyon/the-inner-canyon/recreation/river-running
[2] http://www.moon.com/destinations/grand-canyon/the-inner-canyon/recreation/hiking-and-backpacking/tonto-trail