Spin and Counterspin
August 15, 2005
The Rocky Mountains, looming and changing shape through the windshield, overpower with dramatic vistas, drop-offs and streaming effects of light. So much grandeur, like too much Beethoven in E flat, finally wears down your forbearance. You long for some little corner of exquisite detail to explore on foot. You will happily settle for the interplay of stone and plant, the garden marooned in the boulder, the rockface sculpted by ice – for it is of such detail that grandeur is composed.
Not so far back in geological terms, the Roaring Fork Valley was filled with ice a thousand feet thick. The pressure of advancing ice usually carves a U-shaped valley, but just below the confluence of the Roaring Fork River and Lincoln Creek, at the Grottos, it struck a particularly resistant strain of granite. Even the combined forces of the glacier’s twin arms were unable to carve more than the tight slopes that pinch to this river bottom. Some 10,000 years ago the glaciers began to melt, leaving glistening rondures of bedrock whose arcs repeat on the skyline. Subsequent freezing and thawing has shattered much of the high rock into talus, drawing the walls closer, increasing the intimacy.
As the glaciers withdrew, pouring cold air from the melting ice, plant communities that had spent the ice age downvalley began to migrate upstream, taking some 2,000 years to climb from the valley’s mouth at Glenwood Springs to the narrows around the Grottos. Even now these plants must endure extreme cold, not just during the long winters, but even on summer nights when cold air spills from the alpine heights in ghostly rivers that parallel the tumultuous thread of water.
The visitor who crosses the Grottos footbridge and starts the Forest Service’s loop trail will soon reach a classically smooth outcrop of granite. The rock’s long parallel streaking near ground level, like faded chalk, was left by the wheels of ore wagons and stagecoaches, for this stretch of trail follows the old stage line between Aspen and the smelters of Leadville. Randomly scattered on this wave of stone are large, sharp-angled boulders scaly with green and black lichen. Seemingly out of context with where they sit, stranded by retreating glaciers, they are known as roches moutonées – literally, rocks turned into sheep.
The open view from this clearing demonstrates the contrast between the sparsely vegetated high slopes, with their dramatic black streaking, and the rich riparian ecosystem between the trail and the river. The groundsoil is thick with bracken, horsetails, Rocky Mountain maple and changing displays of penstemon, paintbrush, yarrow, lupine, bistort, harebell and blooms only a biologist could name. Nestled on the sheets of granite, and sometimes below the roches moutonées, are pockets of vegetation, miniature oases where rock is literally converted into life – first by lichens and mosses, then by successions of plants, most emblematic of which is the small white flower called saxifrage, whose very name means stone-breaker.
The Grottos’ namesake feature is a stretch of former riverbed where the water dove into granite and chiseled a tight, twisting, improbable slot. It may have been the main channel of Lincoln Creek in historical times, for an unproven theory holds that miners diverted the stream to its present location to protect the wagon trail. Whatever its past, it is worth gazing at from above before you plunge in. Fallen logs straddle the cleft; fern bursts from cracks in the walls; moss grows thick on the shadowy overhangs. More logs, half-preserved by the cold, half-decomposed by water, lie in the still pool below in long amber cylinders. You can see where a chunk of granite that has collapsed could be fitted back like the correct puzzle piece.
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Once you have picked your way to the bottom, the air is dank and 10 degrees cooler and your surroundings glimmer in the half-light. Water that passed through here, laden with rocks and grit, scoured these tight walls that pressed the liquid into spin and counterspin, feeling for material it could wear down, carving a series of plunges and vaults that soar overhead. Ice that fills these hollows during the winter sometimes lingers into midsummer, progressively melting away from the walls so as to leave free-standing sculptures, shrinking solids that parody the spaces they filled. A few turns upstream lies a chamber where it is productive to sit and let your eyes roam. The ceiling is a large rock that forms a natural bridge. The trickle of a small stream is slurred by its echo. Directly in front of you, a hole to the sky lets light onto a wall of moss that glows like pool felt. The uncomfortable rock beneath you sends a chill through your jeans: this is a medieval cell with an exit. But the way out is by retracing your steps, for just upstream the pools end and the slot climbs through interlacing zigzag walls to an overworld out of reach.Climbing beyond the Grottos, passing over another granite outcrop with a whole flock of roches moutonées, you arrive at a stretch of the Roaring Fork River that tumbles over a series of cascades and small plunges. Watching the descent of water, forced to curl around one rock, hitting the next one frontally, fanning over it and diving into a new turn, you can trace the gyrations that scoured out the Grottos. The toughness of water and its burden is proven by the fact that granite, fracturing at nearly right angles on cliffs and free-standing rocks, has been smoothed by water into curves and even into knee-high amoeba-shaped pothole-cradling ridges just above the cascades. Immersed in geology, you may be startled by a gray robin-sized bird darting through the spray. The water ouzel, or dipper, skims just over the water foraging for insects, dives to the bottom for larvae and small fish, and builds its nests in streamside crevices. When this bird stands in place, does it rock ceaselessly back and forth because it gains stereoscopic vision by merging its upper and lower views? So goes an unproven theory about water ouzels.
Ice sculptures, cascades, stray rocks, odd birds: the Grottos prove how much variety can be spurred by squeezing a valley. After immersion in geological arcana and botanical minutiae, you can even face the sublimity of the drive home.Bruce Berger’s books include “The Telling Distance,” winner of the Western States Book Award, and “Music in the Mountains,” a history of the Aspen Music Festival. This essay is from the forthcoming “The Complete Half-Aspenite,” to be released at the end of the summer.