THE trail climbed steeply out of the creek’s gully to follow a crest that paralleled the edge of the cliffs. Soon, it gently dropped down to the clear waters of Yosemite Creek where white granite slabs sloped down to the lip of Upper Yosemite Falls. The stream flowed gently over the smooth slabs before suddenly gathering itself to plunge over the lip of this sheer cliff to become the 1,430 foot Yosemite Falls, one of the longest waterfalls in the world. Earlier in the day I had stood at the bottom of the falls, full of admiration for John Muir…