Wednesday morning Catherine picked me up at home and we headed east on I-80, to visit The Source of the North Fork American. Of course there are multiple "sources" of the North Fork, uncountably many, one could say; but if one looks for the ultimate headwaters, for the very highest and easternmost perennial stream, one quickly (with the help of the USGS 7.5 minute "Granite Chief" quadrangle) fixes upon Needle Lake, a little above 8400', in the cirque northeast of Needle Peak (8871').
Although the map labels the perennial stream issuing from Needle Lake as "Chief Creek," its canyon is much the direct continuation of the North Fork canyon. Although its course roughly parallels the Sierra Crest, at right angles to the main thrust of the North Fork, Chief Creek's canyon is large and deep and is not, at first, what geomorphologists would call a "hanging" valley. That is, it is at the same level as the North Fork itself, which latter, otherwise, we would have to consider to suddenly and mysteriously end.
At any rate, I have long (since 1972) regarded Needle Lake as the "true" source of the North Fork American. To get there, Catherine and I would hike east, up the Foresthill Divide, from a pass on the Divide at about 7000', right up and over Lyon Peak, at 8891', thence east another mile to Needle Peak, scrambling from the summit lava flow down the steep walls of the cirque to the lake.
The upper basin of the North Fork is surrounded by ridges and peaks made of the "young volcanics." These are as old as 30 million years, as young as 3 (?) million years, and are called "young" in comparison with the vastly older "bedrock" beneath the young volcanics. This bedrock is either granite or metamorphic rocks, both Mesozoic and Paleozoic in age, roughly, between 80 million and 200 million years old. There is a "profound angular unconformity" between the young volcanics and the old metamorphic bedrock. For, the metamorphics are typically stratified metasediments, with the strata tipped up on edge, while the young volcanics are also stratified, layer upon layer of rhyolite ash, andesitic mudflow, and both andesitic and basaltic lavas. But these strata are *not* "tipped up on edge," rather, they are often nearly horizontal. Thus they represent not just a simple unconformity--a break in the depositional sequence--but an angular unconformity. And the angle approaches ninety degrees. This, combined with the difference in age, is what makes it, not just an unconformity, not any old angular unconformity, but a "profound" angular unconformity.
I planned to gather samples of several lave flows for Brian Cousens, who is studying the youngest of the young volcanics, in the Squaw Valley area.
We turned off I-80 at the Soda Springs exit, drove out old Highway 40 a little ways, and turned right again to pass through the Serene Lakes subdivision to the Foresthill-Soda Springs road. We followed this rough rough road down into, and then across, the upper basin of the North Fork, passing The Cedars and its many "no trespassing" signs, crossing the steel bridge over the North Fork, and then, a mile or less past the river, bearing left on the road which climbs up to the pass on the Divide. A sign reads "Tevis Cup Trail 2.5 miles" or something to that effect; for this trail feathers right into the pass, and then follows the Divide west.
At the pass we parked, saddled up, and began the climb to Lyon Peak. There was quite a display of wildflowers. The sun was intensely bright, but a stiff wind flailed away at us and kept us cool. The flowers distracted us from the sound and sober business of hiking, and we made slow progress up the ridge. Curious peaklets and cliffs and spires of andesitic mudflow studded the ridge in places, and as we climbed, we went back in time as it were, and species of plants which were past bloom and had set seed, where we parked, were still in full bloom, only a little higher.
Lupine, Mules Ears, Indian Paintbrush, and Mustang Mint were conspicuous and abundant, but many other species were present. There was a classic, Alpine, almost high-desert feel to the terrain, so rocky and barren, and the plants almost all much given to forming mats and cushions.
Snow Mountain rose into view, and as we zig-zagged back and forth across the summit of the Divide, we would see, alternately, the headwaters of the Middle Fork, and then the North Fork, of the American. Picayune Valley and Mount Mildred were just to the south, and then, as we rose higher, the Crystal Range, Jack's Peak, Dick's Peak, Pyramid Peak and Tallac all came into view. To the north, Castle and Basin peaks could be seen, with Mt. Lola just beyond. Red Mountain and Devils Peak were aligned with one another to the northwest, while English Mountain and the Sierra Buttes came into better and better view as we climbed. At the top of Lyon Peak we were even rewarded with a dim view of Mt. Lassen to the north, and the Sutter Buttes to the west, and Banner Mountain, near Nevada City.
However, long before we reached the summit, we met The Three Geologists, a teaching assistant (Scott Herman) and two students from U.C. Santa Barbara. The students were engaged in field mapping the area, and were identifying the many and various components of the young volcanics, their contacts with other components, the position of the underlying bedrock, etc.
After a nice chat we all continued towards Lyon Peak. Catherine and I paused at certain noble cliff of andesitic mudflow, which rises to a sharp pinnacle which can be seen from far and wide. To the north, the deep valley of an unnamed tributary of the North Fork fell away below us, and, nearly a thousand feet down, a curious plateau, or complex of terraces, made of several (?) lava flows, held two small ponds. Glacial scouring had planed down the lava to form the terraces, and faint curved lines could be seen, on their flat tops.
Snowfields were many, most small, but we managed to hike directly over the snow for a time, and at last were at the summit talus fields, crowned with three small peaklets, the easternmost the highest. The summit is made from one or more flows of andesite. There appears to be some glacial smoothing of the summit itself. We scrambled up to the western summit and were rewarded, immediately, with a view across the north end of Lake Tahoe to the Carson Range, and a huge cloud of smoke boiling up just beyond. It looked to be rising from near Highway 50, where it descends the east side of the Carson Range to Carson City.
Stiff south winds were stretching the upward-boiling cloud into a long north-trending pennant of smoke. After taking a sample of andesite, admiring all the views, and discerning the snowfields on the south face of Mt. Lassen, framed neatly between English Mountain and the Sierra Buttes, we continued east towards Needle Peak.
Long traverses over talus eventually brought us to the Needle itself. This too is part of a lava flow, severely eroded by glaciers, and the flow is evidently perched right on top of a stratum of the much more ubiquitous andesitic mudflow. I took a sample. We did not climb to the summit itself, but rounded just below to the east and found an easy descent into the cirque, to Needle Lake.
This small deep lake makes an ellipse in a meadowy flat with groves of graceful Mountain Hemlock, with their seemingly Japanese artistic flair of branch and cone. Snowfields and lava cliffs ring around the lake on the south and east, some of the snow still touching the water, and the lake is rather vigorously overflowing into Chief Creek, which is still bridged over by snow in places. Red Heather was in conspicuous bloom, along with some lovely daisy-like flowers, dwarf lupines, and many other species; yet it was clearly still before the peak bloom.
It was a relief to find the shelter of trees after a long time on the sun-swept, wind-swept crest of the Divide, where only a few stunted trees grow in the passes, and no trees at all live along the summit ridge itself. We rested and then wandered, taking many photographs. One could see Tinkers Knob, a couple of miles to the north, neatly framed between groves of hemlocks to either side of Chief Creek.
The sun was westering, and it behooved us to wester as well, so we saddled up again and followed a use trail along the base of the cliffs north of the Divide. We crossed several minor wet meadows, and wandered through forests dominated by hemlock and Western White Pine, occasionally following a well-defined trail, but also just making our own particular way. It is pretty easy going up there, One has to avoid the dense thickets of willows and Mountain Alders in the wet areas, but over talus or through forest, it is easy.
Eventually we were forced to climb a prominent spur ridge springing away north from the summit of Lyon Peak. A forested pass is just to the north of Lyon, at about 8400'. On the far side we dropped into the Valley of the Volcanic Pond, and found and lost "use" trails which allowed us to wind in and out of minor ravines and circle around the head of the valley, without losing too much elevation. Finally a short ascent through a grove of Red Fir brought us to The Terraces and the Volcanic Pond.
Again we rested, admiring and photographing the great view, with Lyon Peak high above to the southeast. I took a sample of the lava, beside the larger pond. However, the sun was rapidly lowering, and so once again we left somewhat sooner than we would have liked, and, by climbing up the ridge of these terraced lava flows, we were able to traverse across to the main Divide, well below the Cliff of the Pointed Pinnacle, and then follow the use trail down to Catherine's truck.
We had made a hike of nearly ten hours, covering perhaps seven or eight miles altogether, on the upper Foresthill Divide, visiting what could be regarded as The Source of the North Fork American river.