Many stream/river crossings on the John Muir Trail can be made with dry feet, if you find the right place to cross and don't fall! Mile 30.
At some points along the Lyell Fork, the river takes a break from it's course through the meadow to cascade down granite slabs. Mile 29.
The John Muir Trail/Pacific Crest Trail follows the Lyell Fork through most of Lyell Canyon. Mile 28.