Fowler Trail - Self Guided Nature Walk - 1.4 Miles Round-Trip

The walls of Eldorado Canyon State Park reveal its 1.7 billion year history in just a one mile span. Exposed granite at the canyon's west end was formed by seeping magma that cooled and solidified quartz, feldspar and biotite into igneous rock. Overlying this granite is 1.6 billion year old quartzite, which began as a thick layer of eroded sand that was buried, compressed into sedimentary rock and pushed closer to the earth's core. Rising heat and pressure transformed this layer into metamorphic rock, a gray quartzite found at Supremacy Rock and Rattlesnake Gulch.

300 million years ago the Ancestral Rocky Mountain uplift, about 30 miles west, bore granite mountains that slowly eroded, depositing thick layers of sand and pebbles downstream. These sediments were compressed into a layer of sandstone known as the Fountain Formation, famously exposed in Boulder's Flatirons and Golden's Red Rocks Amphitheater. Hematite, or iron ore, gives these rocks a distinguished red hue. Most of Eldorado Canyon's highest cliff walls are part of this formation.

280 million years ago sand blew west from eastern deserts, settling as dunes over the Fountain Formation and compressed into sedimentary rock over the next 40 million years. This newest layer, known as the Lyons Formation, is visible at the mouth of Eldorado Canyon. 65 million years ago a second Rocky Mountain uplift forced horizontal layers of the Fountain and Lyons formations upward, exposed today by the erosive force of South Boulder Creek. These tilted layers usher water 8,000' underground, where it's forced back to the surface as an artesian spring.

The Fowler Trail - self guided nature walk traces a short section of South Boulder Creek east through the canyon with revealing perspective on the towering cliffs above. Free interpretive brochures at the Visitor Center explain the canyon's complex geology, rich biology and storied human history. The Fowler Trail is ideal for curious minds and families of any age and skill level.

The Fowler Trail begins at the Rattlesnake Gulch Trailhead and heads east on level track past the Rattlesnake Gulch Trail split. 12 marked points along the way correlate with an educational brochure. The trail continues east and wraps just south of the canyon mouth to the Eldorado Canyon State Park boundary (.7 miles : 6,110'). Retrace your steps back, or continue on the Fowler Trail 1.3 miles to its eastern terminus at the Eldorado Mountain Trailhead. Those seeking an even longer adventure can improvise routes via connections with the Goshawk Ridge and North Spring Brook trails, .95 miles and 1.45 miles from the Rattlesnake Gulch Trailhead, respectively.