"Even below the mogollon rim, where many Arizona wildlands support perennially flowing creeks, the Fossil Springs Wilderness is unique. Two small tributaries, Sandrock and Calf Pen, come together to form a basin that narrows sharply before widening into a stunning oasis. Widely spaced springs gush into the creek, producing a flow of 20,000 gallons per minute at a constant temperature of 72 degrees Fahrenheit.
Opened up by the springs, the creek flows down into large pools overhung by alder, sycamore, netleaf hackberry, cottonwood, Arizona walnut, bigtooth maple, and oak. Canyon grape intertwines tree branches; ferns cascade from rock crevices; blackberry bushes crowd the banks. In warm seasons, monkeyflower and columbine sprout along the creek bottom. On the faces of the sheer cliffs above the springs, tangled thickets of manzanita discourage hikers with any notion of bushwhacking into the oasis. This trail guide covers an area with 9.5 miles of trails."