[written July 8, 2007]
The orchidaceous and salamandrine Onion Valley area of the North Fork of the North Fork of the American River (the NFNFAR) has been heavily glaciated, several to many times, in the last few millions of years. Paradoxically, bold bedrock outcrops are uncommon; far more likely one will see glacial till, which covers 95% of the bedrock, and which often contains a myriad of granite boulders, dragged south across the Yuba-American Divide from sources in the upper South Yuba basin.
Commonly, the glacial till supports a rich coniferous forest.
Drive south about six miles through such till, from Emigrant Gap, on I-80, to reach Onion Valley, which straddles the divide between the NFNFAR and the East Fork of the NFNFAR. Here began Tahoe National Forest's Monumental Creek Trail, which climbed away north to Mears Meadow. This trail was abandoned, in stages, and is no longer passable. Also at Onion Valley, one finds Bradley & Gardner's Placer County Canal, which can be followed east into Monumental Canyon and the East Fork, or followed west into the NFNFAR, and beyond; once it could be followed right to Dutch Flat and Gold Run.
To the south and east, the Shoo Fly Complex of varied metasedimentary formations forms the bedrock; to the north, the Emigrant Gap Mafic Complex (of igneous intrusive rocks); to the northwest, one of the younger plutons of granodiorite. This pluton underlies a few miles of the uppermost NFNFAR, and at least a few of the infinitude of granite boulders embedded in the till around Onion Valley, must derive from this pluton.
Hiding beneath the glacial till, near Onion Valley, is the contact between rocks of the Emigrant Gap Mafic Complex, and rocks of the Shoo Fly Complex. Now, the Shoo Fly is often strongly layered, being sedimentary, and parts of the Mafic Complex are strongly foliated. Even though both igneous, and intrusive, these mafic rocks can mimic sedimentary rocks, with their many parallel slabs, their folia, their "leaves." Forest Road 45, near Onion Valley, cuts a dike of very light-colored, fine-textured igneous rock, so foliated one could easily mistake it for some kind of sedimentary deposit. This type of dike may be derived from the Mafic Complex, although it itself is not mafic; quite a number of similar dikes cut the country rock to the northeast, along Monumental Ridge, just east of the Mafic Complex.
Directly up-ice from Onion Valley and the related, pater-noster meadows which extend away north, is a resistant mass of the Mafic Complex. This resistant mass forms a cliffy wall, mostly hidden from easy view, in the forest, and associated with this gabbro, say, or peridotite, possibly, is a mass of dunite, another mafic intrusive. Dunite weathers to a light brown, or even orange, and remarkable examples of these rocks are found to the north, above Lake Valley Reservoir, on the slopes of Black Mountain. (Black Mountain gets its name from the dark, heavy, iron- and magnesium-rich rocks of the Mafic Complex.)
The cliffs have shed a rough talus of dunite boulders, then, within the last twelve thousand years. These boulders flank the upper meadow, above Onion Valley to the north.
To me it seems that the "resistant mass of the Mafic Complex," which includes some dunite, caused the ice to ride high, only then to plunge down, gouging out the basins of the wet meadows, and finally damming them with terminal moraines, when the ice at long last melted.
In those wet meadows a wealth of wildflowers is in bloom. Masses of tall Leopard Lilies dangle their large orange flowers, spotted petals curved back upon themselves, the six anthers hanging below: this is a favorite of the Swallowtail butterfly. Bigelow's Sneezeweed is a concoction of almost supreme geometry, the disk flowers arranged in systems of opposed spirals inscribed upon a sphere: a sort of daisy, with a tiny charmed temple set at its center. Blue-eyed Grass dots the thick turf of the glacial meadows. Milkweed breaks into insect-luring bloom. Some species of orchid, maybe Ladies Tresses, haunts the wet meadows, with tiny beaked flowers, mainly white in color, spiraling tightly along a thin, straight stalk, up to eighteen inches tall. One such orchid has easily a hundred flowers. In places, dozens of these delicate orchid-stalks glowed in the shade, little ghost-wands of white rising above the greensward.
Hence the meadows, and the woods which embrace the meadows, are orchidaceous. How much more so, when we recall the many Rattlesnake Orchids which prosper in those very woods. Yes, the area is certainly orchidaceous.
It remains to show that the area is salamandrine, a word I coined, heh heh, which means "bearing salamanders," or "[land] of salamanders." Or possibly, "[partaking] of salamanders."
Salamandrine is better than salamanderiferous. Note: one should never literally "partake of salamanders," for they are poisonous.
Recently my son and I explored some of Sailor Ravine, west of Onion Valley, and below the line of the Bradley & Gardner Canal. We parked along Forest Road 19, south of Emigrant Gap. Sailor Ravine is a tributary of Fulda Creek, Fulda being one of the principal tributaries of the NFNFAR. Each had a glacier flowing down it, thirteen thousand years ago. In fact, the glaciers coalesced into a single ice sheet above the dividing ridges. Howsoever ... scouting for the "Trail to Monumental Camp" depicted on one of my old maps, we descended Sailor Ravine to where it plunges into Fulda in a series of waterfalls and cascades, dropping hundreds of feet.
There was bedrock exposed, along the creek, above the top of these falls, for a distance of a quarter-mile or so north, into the deep woods; Shoo Fly Complex metasediments tilted up on edge, the stream flowing across the main strike of the strata. In the cool shade of the tall trees, my son and I followed this gentle little stream, and counted 180 Sierra Newts in that quarter-mile of bedrock. Then, leaving the great sunny hollow of Fulda Canyon still farther to our south, and striking ever deeper into the deep woods, the bedrock was buried in till, and we saw no more salamanders.
The one hundred and eighty newts we did see were still in the "keeled tail" form, of the mating season, which should have ended by now, but there they were, five in this pool and ten in that, with bedrock, some kind of meta-sandstone, always exposed nearby, if not flooring the pool. Six inches long, dark brown, with orange and yellow bellies, bulbous eyes, an underwater lizard as it were, but as often or more often, terrestrial in its habit. Their scientific name is Taricha torosa spp. sierrae. Roughly translated, this means "the rough-skinned, dried mummy, of the Sierra."
If we had not climbed, but had descended Sailor Ravine, to Fulda, and then followed Fulda down to the NFNFAR, well, it would have been pretty much bedrock the whole way down, and that can only mean, certainly, an abundance of rough-skinned mummies, I mean, salamanders, the whole way down. The count would rise into the thousands.
Any land which contains thousands of salamanders is "salamander-bearing." The Onion Valley area contains thousands of salamanders. Hence, it is "salamandrine," which was to be proved.