On the Brink

So many adventures to share... so little time to write. An exciting loop through Zion's Parunuweap Canyon and car camping down Hole-in-the-Rock Road are coming.



A recent exploratory bike ride near St. George reminded me that there are always new jaw-dropping views and intriguing adventures to discover close to home if you’re willing to spend some time studying maps and Google Earth’s virtual globe.

Looking south from popular trails near Green Valley, a massive tilted plateau can be seen rising steadily southward until breaking away to, well, I never could place what exactly lies beyond that horizon.

Maps reveal that this hulking mass does have a name—Blake’s Lambing Grounds—and what lies beyond is an impressive vertical drop of nearly 2500 feet straight down to the floor of the winding Virgin River Gorge.

I imagined the view from this precipitous brink and plotted out a 13 mile-long route of dirt roads that would lead me and my trusty two-wheeled steed there. Turns out, my imagination didn’t give the view justice.

Start the ride in Bloomington, where the western extension of Navajo Drive crosses a cattle guard and turns to dirt. Plenty of space near the flood-control pond allows you to park and unload your bike.



The colorful rocks enveloping the route, including the striped badlands of the Triassic-age Moenkopi Formation, tell a fascinating story of what southwestern Utah was like more than 200 million years ago. Instead of the majestic mountains, iconic plateaus, and deep canyons seen today, southwestern Utah was a flat-as-a-pancake coastal plain positioned near the equator on the western edge of the supercontinent Pangea. Sea level would alternately rise, inundating much of Utah with shallow tropical waters, and then fall, placing the shoreline far off to the west.

From the parking area, pedal west on the main graded dirt road, ignoring numerous sidetracks, and wind across a couple of low drainages before dropping into the larger Curly Hollow.

Light-gray Moenkopi siltstone adjacent to the road was deposited by shallow mineral-laden sea water that also left behind an abundance of the mineral gypsum that gives the rock its chalky appearance.

Pass the turnoff for Bloomington Cave and climb out of the wash to the southwest. The Moenkopi siltstones around you are now mostly red. Poke around and you can almost always find ripple marks on the rock surface indicating the region was not covered by a stagnant sea, but had water flowing over its surface, such as streams or oscillating tidal waters.

As you roll into a broad flat that is a popular staging area for ATVs, look ahead and slightly to your right for a dirt track climbing the rocky slope to the west. Staying right at a fork, start cranking away up the slope.



Leaving the red rocks behind, the road climbs the tan Virgin limestone, a subunit of the Moenkopi. After cresting the initial climb, the road descends slightly, cutting across several layers of limestone that document a sea teaming with life. Search through the boulder-littered slopes near the road to find bits of fossilized clams and crinoids or “sea lilies.”

After skirting around terraced hills of Virgin limestone, traverse one last band of red Moenkopi that was deposited on and near the beach of a Triassic sea.

Underlying the Moenkopi are the light-gray siltstones and occasional dark limestone ledges of the marine Harrisburg Member of the Kaibab Formation. The contact between the Triassic-age Moenkopi and Permian-age Kaibab rocks represents a nearly 20-million-year gap in the geologic record, created when global sea level dropped dramatically. Instead of sediments being deposited during this time, 100s of feet of rock were eroded away. Sometime during this lost interval, the world’s largest mass extinction occurred when more than 70 percent of all animal species perished.



The road soon plunges into West Mountain Valley Wash—a deep canyon incised into the Harrisburg Member. As you climb out, look across at the northern wall of the canyon for Harrisburg strata sagging into a hole. Although their origin remains uncertain, geologists believe that these “collapse structures” may root into ancient sinkholes developed in limestone some 3000 feet below the surface. Hundreds of such features have been found in the area; some are known to host uranium and copper ores.



Just before reaching the power line, you’ll leave the Harrisburg Member behind and encounter the oldest rock unit you’ll tread across for the day: the Fossil Mountain Member of the Kaibab. This aptly named blue and gray limestone is full of the remains of shelled sea creatures and corals that inhabited a warm tranquil sea.

Follow the power line to a fork, bear left, and start the steady 1.5-mile climb up into the heart of Blake’s Lambing Grounds.



In early spring, abundant grasses make it easy to understand why the area makes great early-season range for livestock. While the scenery may not be postcard material, the subtle lines of this treeless high-desert prairie has a romantic charm all its own, and it is markedly different than the red, sandy deserts just a few miles back.



Four miles from the power line, fork left and drop into a small canyon. Pass through a gate and in 100 yards or so, turn onto a rough track climbing the hillside to the right. The road climbs a small wash, bends southward, and begins to parallel the plateau’s western edge where fleeting glimpses over the rim foreshadow the colossal vista ahead. The increasingly rough road crosses into Arizona and reaches the overlook after topping a final set of steep switchbacks.



Pull out your lunch, find a comfortable slab of chert-studded limestone and be confounded and amazed. Confounded by the complexity of the scene where the simple, orderly Colorado Plateau clashes with the faulted and mangled Basin and Range; and amazed by the shear immensity of the void in front of you, carved out by the seemingly diminutive Virgin River.



To the south, the broad, flat-topped Black Rock Mountain promptly transitions into the jagged Virgin Mountains immediately to the west. The towering southern Beaver Dam Mountains form the western horizon. The wide Cedar Pockets Wash beneath your feet is partially adorned with salmon-hued Queantoweap sandstone, reminiscent of, but about 100 million years older than the more famous Navajo sandstone of Zion National Park fame.



After soaking in the views, retrace your steps, and enjoy the fast and mostly downhill descent back to civilization.


Map of the route: