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One steamy morning in early July, I stand on a footbridge a few hundred feet inland of the lake watching the sun seam its rays into the birch crowns on the hillsides around the lower gorge of the Temperance River. Frothy cascades push through a neck of mocha-brown rock just upstream of the bridge and after rounding a sharp bend send lacy ribbons of white foam swirling lakeward. A few cedars hug the gorge and scattered firs and spruces create splinters of darkness amid the birch trunks on the surrounding hillsides. Like the gorge and hillsides, the rocky outcrops around the river’s mouth are steeped in small contrasts that say as much about the character of the shore as does the broad sweep of headlands, points, and coves.

The Temperance today is a mere shadow of the raging meltwater river that coursed across the bare land in the wake of the glaciers’ retreat. That early river emptied into a small lake at the ice-free southwestern end of the rift basin and reached five hundred feet above the present shore.1 Though the lake initially drained south, as the ice sheet retreated to the northeast over the next several thousands of years, new outlets were uncovered to the east and the water level gradually dropped to more than two hundred feet below the present shore. To reach down to its falling outlet, the Temperance had to cut through heaps of glacial sediment and bore deep into the bedrock.2 In the process, it carved the narrow, sun-starved gorge through which it now plunges a hundred and sixty feet in the final half mile of its journey toward the lake. 


“Nature’s Drill Bits” reads the caption on an interpretive sign along the trail that leads up the gorge on the other side of Highway 61. The river’s Anishinaabe name is Kawimbash or ‘deep hollow’ and the sign explains that the gorge formed from the joining of potholes cut by rocks that swirled in the currents of the early river. Eventually, however, the river swept most sediments within its reach into the lake and lost its former erosive force.3 Today, its light sediment load and deep underwater drop into the lake prevent a permanent sandbar from building up at its mouth. From the bridge, I can make out a barely visible fan of rose-colored gravel inland of the gorge’s western tip. A second gathering of gravelly sediment creeps out from the beach that parallels the western leg of the eroded v through which the river enters the lake. Both sandbars become visible mainly when the lake is low and are easily washed away by storm waves or floodwaters that push through the narrow gorge. The name Temperance, which first appears in an 1864 report on the geology of the Minnesota shore, is an apparent reference to the temperance movement and the river’s lack of a ‘bar.’4

Turning from the gorge, I climb a steep set of wooden steps through the softly lit understory of the hillside to the east, then skirt the larger of the park’s two campgrounds to follow a second set of steps down to the lake. Thick birches with white and silvery-gray bark peeling off in tight curls dress the latter hillside. On the shore, a broad craggy platform extends east toward a cove while rising to the west until it pinches off along the forest. Shrubs and flowers have claimed nearly every thimble of soil on the small slopes and ledges that bound the side of a long, shallow pool toward the platform’s western end. Overlapping butterwort and bird’s eye primrose rosettes brighten mossy soils on the lower rock while three-toothed cinquefoils, wild strawberries, round-leaved sundews, and Kalm’s lobelias crowd nearby pockets and small ninebarks, alders, and serviceberries favor slightly higher ground. A tiny northern plant with delicate lavender-blue flowers, the lobelia was named after the Swedish-born Finnish naturalist and economist Pehr Kalm, who in the late 1740s traveled in North America gathering seeds and plants for use in Swedish agriculture.5 Also known as an Ontario or a brook lobelia, in Sweden it’s called a gräs lobelia after its grass-like stem.

While edging my way along the lower rock, I also spot a cluster of Hudson Bay eyebrights. The eyebrights stand only two to four inches, but may grow slightly taller over the summer. Each hairy burgundy stem bears tiny pairs of stalkless leaves and a bushy spike of leaves at the top. Lurking amid the spike and upper leaves are long burgundy-brushed bracts with gaping tubular flowers that measure a mere two millimeters. Each flower ends in a pale purple upper petal with a backward-bent rim and a flaring lower lip with three white lobes and a honey-yellow dot with a purple vein to each side. The petite flowers and stalkless leaves give the eyebrights an oddly primeval look. Yet the Eyebright genus includes many similar species with a primary range on subarctic and alpine meadows. The Hudson Bay eyebright looks nearly identical to the non-arctic tartary eyebright, which has spread rapidly from its inland range onto the Minnesota shore, especially in areas disturbed by humans.6 I take the plants by the pool for Hudson Bay eyebrights, mainly on account of the fine hairs on their leaves. But a definitive confirmation of their identity would require genetic testing.

As I slowly walk east from the pool toward the cove, a few wood lilies and a blue flag color the edge of the hillside and scattered shrubs and flowers dot corners and crevices around short walls and mounds on the uneven rock. Except for near the water, much of the platform sits high enough to be covered in a thin coat of gray lichen and blackish stain. A few additional large pools appear toward its eastern end, but none support the density of vegetation of the pool to the west. Though I keep scanning cracks and dips for flowers, I soon mostly search the surface for fresh patches of unweathered rock, places where the platform sheds its brooding tenor and reveals sometimes startling slivers of light and color.

Thin, parallel reddish bands arc across several feet of slightly raised lavender-gray rock, remnants of the wrinkled outer skin that formed on the surface of a lava flow as it spread across the earth. Once erupted, the thin basalt flows that laid down the Minnesota shore quickly began to cool and harden on its surface, acquiring a thin crust that wrinkled up as hotter molten lava moved it along from underneath. Though often impressive where it appears, the ropy skin has mostly eroded away elsewhere on the shore. A few short walls further to the east display crusty washes of clay or minerals carried by fluids into empty pockets in the cooling lava. Though most washes contain a muted mix of whites, grays, browns, and creams, one wall boasts a shaggy panel of glossy rice-like tendrils arranged into swerving bands that range in color from burgundy-brown and lavender to black-and-cream mottled and white. A second, larger panel has a pale blue-gray base with patches stippled in thin diagonal spikes in peach and white.


As I continue my walk, I also see a large patch of clean rock with a cracking surface freckled in mustard-yellow, pale orange, and rose. Glowing subtly against the laden surrounding rock, the patch creates a striking window into the interior of the basalt, though I suspect it won’t take long for its skin to begin to tarnish. The clean patches and crusts are small and easily obscured by short walls or mounds. As so often, each time I retrace my steps across the same stretch of rock I’m reminded of how much I miss from one visit to the next. A corner of rock can have seemed unremarkable in the past only to present an entirely new impression when approached from a different angle or condition of light, weather, or I even think personal mood.


Though I’ve seen the mustard-yellow patch before, this time its brightness astounds me. I open my notebook and begin to jot down a few reflections. I used to think that taking notes was mainly a means of creating a record by which to remember a place. But as I returned to the same headlands and ledges, just as often as I recorded new observations of a familiar stub of rock or flower, I wrote down figures, descriptions, and impressions I knew I already had in a previous notebook, if not two or three. The urge to describe and reflect, I discovered, was at its core an instinctive response to wonder and the innate desire to draw the land close, to lean ever deeper into reverence. 

From the slender cove that bounds the eastern end of the platform, a bulge of pitted rock wraps inland toward a long cobble beach. The beach draws far fewer people than its counterpart by the river’s mouth, but in a sign of how routine-bound my walks have become I haven’t explored it in years. Just before reaching it, I instead stop at an outcrop that dips lightly lakeward in the form of dark charcoal-brown mounds that mark the tops of eroded columns in the basalt. Myriads of small pits identify places where waves have plucked amygdules from the surface, giving the outcrop a distinctly pocked look. A few white and peach-colored veins and patches fill in dips between the low mounds, and here and there near the water the rock loses its dull skin to reveal smooth patches of lavender and red-brown basalt with bright amygdules and splotches. As storm waves continue to whittle away at the rock, eventually the lakeside amygdules too will weather out and leave behind empty pits.

Birches and ninebarks with fuzzy clusters of white flowers brighten the edge of the forest along the upper rock, yet except for around a few nearby pools, the outcrop’s only vegetation consists of a few clusters of Kalm’s lobelia and harebells. Harebells are common on coastal cliffs and ledges, where their long rootstocks and agile stems help them withstand fierce winds and survive in cracks with bare crumbs of soil. Classically northern flowers, they grew around our cottage in Sweden and to this day stir a deep affection. I wander toward a cluster with open bells ranging in hue from a saturated purple to a heavenly light lavender-blue. 

Unlike most other flowers, harebells and many Campanulas or Bellflowers place their pollen not on their anthers but on a brush of stiff hairs that sits near the tip of their style. While a harebell is still in bud, its stamens lengthen to position the anthers around the style, after which the style elongates and the pollen transfers from the anthers onto the brush.7 The stamens then wither. In one bell that I peer into, they’ve curled up like auburn wood shavings around the balloon-like green ovary at the flower’s base. At the outer end of the purple style that extends from the ovary toward the bell’s opening is a pale lavender brush with light, fuzzy patches of pollen grains and at the style’s tip a green stigma that has begun to open two slits at its end.

Bumblebees are frequent visitors to harebells and as they crawl into an open flower, their large bodies rub against the brush and remove pollen. After pollen grains have been removed, the hairs on which they sat retract into the style.8 The bell eventually completes its pollen-dispensing phase and transitions to a pollen-receiving phase, arcing the lobes of the stigma at the outer tip of its style gracefully back. In the bell that I peer into, the pollen brush is pale lavender and the stigma still largely closed. In a second bell, however, the brush has turned yellow and three distinct lobes begun to arc back from the stigma, while in a third bell the stigma has fully matured to create a splaying three-part cross, ready to take in pollen from a visiting bee. 

Hanging nearly perfectly still in the air, the bells showcase their reproductive parts like delicate works of art. Yet the afternoon forecast calls for storms that will likely send the bells bobbing to and fro, and when I stand up and look inland I can see dark clouds already gathering above the peaks of the Sawtooth range. Deciding to return to camp for a quick lunch in hopes of exploring the river’s western side before the weather turns, I gather up my pack and give the lake a final glance. For now at least, the water still displays nary a ripple, its sun-bathed surface appearing so close in hue to the hazy blue of the eastern sky that I can barely tell one from the other on the horizon.


An hour later, I return to the footbridge and once again stop to watch ribbons of foam merge into the dark waters of the widening gorge. On its forty-mile journey to the lake, the Temperance gathers waters from lakes, bogs, and streams throughout the Sawtooth range. The range forms the northern extension of a series of highlands that blocked the Superior lobe from moving out of the rift basin during the last ice age. Once the glaciers retreated, the thick hilly deposits of sediment that the lobe left along its inland margins were eventually enriched by windblown particles of silt and clay to produce deep, moist, fertile soils of the kind favored by northern hardwoods such as sugar maple and yellow birch.9

The Sawtooths sit within a mixed transition forest that extends in a broad arc around the Great Lakes, separating the deciduous forests to the south from the spruce-dominated boreal forests to the north. Informally known as the north woods, the forest encircles most of Lake Superior but cedes the far northern shore as well as exposed coastal stretches elsewhere to cold-hardier boreal species. In addition to northern hardwoods, its trees in the Sawtooths include spruce, fir, aspen, and paper birch, as well as pine on thin-soiled sites and cedar and tamarack in swamps and bogs.10 Before loggers entered the region, the lakeshore was dominated by a mix of large white pine, cedar, and spruce as well as fir, paper birch, and aspen.11

The cooler, damper coastal forest historically saw fewer fires than forests further inland.12 Once loggers and settlers had removed the forests, intense blazes swept across the land, fueled by the buildup of brush and the stumps and slash the loggers left behind. A lack of seed-bearing trees, heavy browsing by deer, and competition from non-native grasses later kept former stands of white pine and cedar from regenerating.13 In contrast, paper birch spread quickly across the charred land from large crops of wind-born seeds. A pioneer species that had also been early to colonize newly ice free lands, it soon joined quaking aspen in dominating large swaths of the Minnesota shore, including the hillsides around the lower Temperance gorge.

Paper birch is an extremely hardy tree, endowed with an enviable ability to inhabit edge lands and quickly root down in new places. It survives the intense cold and solar radiation of exposed northern landscapes largely thanks to its white outer bark. The white tint of the bark comes from a buildup of the compound betulin, from which the birch or Betula genus takes its name. By reflecting solar radiation on bright winter days, the white prevents dormant cells from awakening and then refreezing when temperatures plummet at night.14 In sun, rain, and fog, birch radiates a tireless glow from amid the somber trunks of spruce and fir. Yet it’s also a fairly short-lived tree that can’t reproduce in its own shade. Having lightened the once-scarred hillsides of the Minnesota shore with the early promise of regrowth, its airy, inviting stands are now succumbing to old age, storms, and disease. Several trees that I see from the footbridge have trunks topped by bare branches instead of leafy crowns.

From the bridge, I follow a path downhill to the beach and walk west toward a series of outcrops that hunker in the sands and reach blunt points into the lake. The outer outcrops have been molded into curves, chutes, and humps by sediment-laden waters and create a far softer impression than the pocked, uneven rock that I saw on the other side of the river. Where out of the reach of ordinary waves, their tops are sparingly covered in stain and pallid gray and orange lichen. But where low-lying and clean, they instead shift between yellowish and pale lavender tints of gray and when seen under the sun’s bleaching rays can take on exquisitely light casts.

On flatter outcrops higher on the beach, thin peach and white veins outline the polygonal patterns of columns in the rock. The same minerals sprinkle the surrounding surface with amygdules and create a few short, lightly swerving vertical streaks at the base of a short wall. Known as pipe amygdules, the streaks formed in tube-like cavities left by gas bubbles that struggled to rise up through the sticky lava that developed where the base of a lava flow came into contact with the already solid top of the flow below.15 Instead of amygdules, some humps sport smooth raised knobs in pale green, gray, or red. An outcrop along the water is covered in rough-cut reddish knobs that resemble rock candy. The knobs are made of minerals such as quartz that proved more resistant to erosion that the surrounding basalt. All along the beach, the pale humps and bands in shifting hues and variously colored knobs, veins, and amygdules give the rock a distinctive flair. 

It’s a short walk from the outcrop with the rock candy to the end of the beach and a footpath onto a low truncated ridge. I quickly reach the far side of the ridge and look down on a rocky cove with a smooth, gently dipping floor of pale, rose-tinted gray basalt. On nearing the water, the rock ripples with folds and knuckles separated by dips with cupfuls of spray. By now, the sun has vanished into a thickening blanket of clouds and the breeze begun to pick up. As I look on from the ridge, a light burst of spray stains a pale knuckle with chocolate-brown drops that evaporate quickly in the heat. 


The small cove is the first of three coves west of the beach. Though each cove has its own character, all three are bounded by tall ridges and have rocky floors that tend toward smoother contours and paler hues. Like the outcrops on the beach, the floor of the first cove is peppered with vesicles and amygdules. I make my way down the inner ridge and wander around its far side tracing white veins that join into threadlike webs. Bands of hardened clay fill in fissures and thin, lacy red lines outline short white bars with crystals that gleam in tints of pearl, orange, and rose. Though the amygdules and veins are well exposed today, summer waves can wash gravels high onto the rock and mostly conceal them from view. 


The second cove has a more open feel and fewer amygdules. But in keeping with its distinct character, as I descend the uneven ridge that separates it from the first cove, I instead see an impressive collection of oblong red bands and irregularly shaped splotches. The bands and splotches measure anywhere from two to three inches to a foot and a half or more. Known as oxidation halos, they developed when fluids rich in iron oxides flowed along parallel cracks in the cooling lava and seeped inward to stain the rock. Though some bands are fainter or more diffuse, many create crisp shapes with bold red margins. The smooth, pale basalt with its red halos looks different enough from the dark, pitted outcrop by the beach on the far side of the river that I could easily have taken it for an entirely different kind of rock.


From the halos, a dipping plain stretches south toward massive blocks that jut lakeward from the cove’s inner ridge to conceal a shallow room bounded on three sides by thick walls. The room’s sloping floor includes diffuse red halos and where it meets the back wall reaches into a wide cave with a two-foot high opening. Dark and musty with seepage, the cave extends back for at least seven feet before ending in a collection of boulders and loosening chunks of rock. As I sit down in front of its opening, the surrounding coastline disappears from view until all I see is open water. The small room shields me from the quickening wind, but restive waters slosh along its lower slope and send occasional shattered panes of spray onto the rock. Before long, I hear the first distant rumble of thunder. 


Not wanting to miss the final cove, I gather up my pack and quickly make my way onto the third ridge. The ridge is broader than its first two counterparts and includes a few water-filled potholes and dips on its lower reaches. Young birches and stunted spruces shudder along the edge of the forest as I briefly stop to look out on the rocky slope to the south. With a rough, irregular surface that turns smoother and paler toward its far end, the slope marks a final stretch of broad, dipping rock before the coast transitions to lower and narrower outcrops beyond the boundary of the state park. Though it affords some shelter, unlike the first two coves it lacks walls on three sides and, I suspect, may not actually qualify as a cove. 


Runoff from a wetland in the forest to its back leaves shallow pools and large patches of algae and moss on its more level upper reaches, while often staining the rock below with dark bands and splotches. For many years when looking across the slope, I mainly saw the rougher rock at the near end and the runoff and splotches. But then one day when the runoff had mostly dried up, I made my way partly downslope and saw to my surprise that the surface of the rock was nearly entirely covered in oblong red halos. The slope this afternoon still has a few wet splotches, but the most impressive display of halos is dry and clean. 


The halos sit within irregular rectangular boxes made of squiggly white veins that fill in thin cracks in the surface. Two columns of boxes can be easily made out, one on either side of a nearly seven foot-long white central vein. A third, less distinct column remains partly obscured by runoff to the right while another column to the left is interrupted by a dip in the rock. Together the two clean columns include a total of ten boxes, each with its own halo. The largest boxes measure about five feet long and two to two and half feet deep. Less distinct white veins sometimes outline thinner boxes within the main boxes, and shorter veins also shimmy across the surrounding rock. The pattern becomes weaker and less linear toward its bottom edge and sides, where the halos grow fainter and the veins begin to meander. But even if not as crisp, the same pattern of white boxes and red halos covers large areas of the lower slope.


I walk around measuring boxes and sketching columns, caught up in the slope’s small universe of pale humps and soft halos until the thunder draws nearer and I finally stow my notebook and prepare to return to the river’s mouth. On reaching the edge of the forest, I stop beside an old birch and look back at the slope. The halos have faded into the distance, but the pale basalt still holds a lingering light.  


1. John C. Green, “Why is Lake Superior?,” Minnesota Conservation Volunteer (July-August 1978): 16.


2. John C. Green, Geology on Display: Geology and Scenery of Minnesota’s North Shore State Parks (St. Paul: Minnesota Department of Natural Resources, 1996), 47-48.

3. Jim Miller, “What’s This Rock Too?: Unraveling the Geologic Story of Minnesota’s Central North Shore” (workshop, North House Folk School, Grand Marais, MN, August 17-19, 2018).


4. Warren Upham, Minnesota Geographic Names: Their Origins and Historical Significance (St. Paul: Minnesota Historical Society, 1920),, 143.


5. Richard A. Jarrell, "KALM, PEHR," in Dictionary of Canadian Biography vol. 4. University of Toronto/Université Laval, 2003-. Year of revision 1979.

6. Katy Chayka, Euphrasia hudsoniana, Minnesota Wildflowers,; Euphrasia Hudsonina var. ramosior, Rare Species Guide, Minnesota Department of Natural Resources,

7. Claudia Erbar and Peter Liens, “Portioned pollen release and the syndromes of secondary pollen presentation in the Campanulales-Asterales complex,” Flora 190, no 4 (1995), 326; Yvonne Nyman, “The Pollen-Collecting Hairs of Campanula (Campanulaceae). II. Function and Adaptive Significance in Relation to Pollination,” American Journal of Botany 80, no 12 (1993), 1437.


8. Yvonne Nyman, “The Pollen-Collecting Hairs of Campanula (Campanulaceae)," 1437.


9. Chel Anderson and Abdelheid Fischer, North Shore: A Natural History of the Minnesota Superior Coast (Minneapolis: University of Minnesota Press, 2015): 112-14, 132.


10. “Superior National Forest,” Nature and Science, Vegetation, USDA Forest Service, accessed October 1, 2019,


11. John Myers, “New Vision for the North Shore,” Minnesota Conservation Volunteer 77, no. 455 (2014): 10; “Natural Vegetation of Minnesota: At the Time of the Public Land Survey 1847-1907,” Map, Biological Report No. 1, Minnesota Department of Natural Resources, accessed February 10, 2024,


12. Myers, “New Vision,” 13.


13. “Restoring Conifers along Lake Superior’s North Shore," Sugarloaf: The North Shore Stewardship Association, accessed December 3, 2019,


14. Michael Snyder, “Why are Paper Birches so White?” Northern Woodlands (Autumn 2010): 15; Michael Wojtech, “The Language of Bark,” American Forests (Winter 2013),


15. Miller, “What’s This Rock Too?”

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