Recently I wrote of having corrected an error concerning the courses of two major mining ditches in Green Valley, on the North Fork American south of Alta and Dutch Flat. I had mistakenly identified a certain high ditch in the center and west of GV as the "Green Valley Blue Gravel Mine" ditch, and, knowing this certain ditch to run west to some hydraulic diggings, at the very west end of Green Valley, across the river from the Gold Rin Mine, I had named those diggings the GVBGM.
But I was wrong. The GVBGM ditch cuts across some remarkable limestone (really, marble) cliffs at the very east end of GV, and terminates near GV's center. A good part of my mistake derived from the impenetrable brush on both ditches, in the middle of GV; one simply could not reasonably follow either one. Only repeated efforts over the last year finally corrected my mistake and properly distinguished between these two, separate ditches.
Green Valley is quite an interesting place. The canyon widens here, in the weak serpentine of the Melones Fault Zone, which zone makes a long linear belt running north and south across all the major canyons in this part of the Sierra. It is sometimes called the Feather River Peridotite, because it cuts across most all the Feather River country, as well as the forks of the Yuba and American rivers. Whether serpentine or its close relative, peridotite, the rock is exceedingly rich in iron and magnesium and poor in quartz, and probably represents a cross-section of ocean-floor basalt, welded to North American during plate subduction, some 150 to 200 million years ago. Like most of the metamorphic rock in the Sierra, this presumed slab of ocean floor is turned up on edge.
At any rate, the canyon widens, and in Green Valley there are extensive deposits of glacial outwash sediments. Contrary to usual thinking, these sediments are gold-bearing. And they were mined like crazy in the olden days. In fact, the sediments, geologically, very young, as little as 12,000 years old, perhaps as much as 800,000 years old in the highest deposits--the sediments are so voluminous as to have merited hydraulic mining.
When I realized this, in 1976, I found it so extraordinary that I set out to contact "real" geologists, so that such an extraordinary thing--hydraulic mines in Ice Age gravels--could be studied properly. Since then, I have gradually come to realize that the phenomenon of hydraulic mining in Pleistocene glacial outwash is not at all unheard of in the Sierra, or elsewhere. Still, these outwash deposits merit a close study.
Green Valley is directly upstream from Giant Gap, a narrow gorge about 2200 feet deep; there are no glacial outwash deposits worth mentioning in Giant Gap, for, how could they cling to the sheer cliffs? The contrast between the two parts of the North Fork canyon is extreme, and extremely attractive. In Green Valley, the great sediment load during times of glaciation overwhelmed the North Fork's ability to transport those sediments; hence a kind of sinuous narrow floodplain of glacial outwash developed, within the canyon; and in Green Valley, the floodplain broadened, to a width of half a mile or so, and the river meandered back and forth across it. Then the glaciers would melt away, the sediment load would return to normal, and the meandering North Fork would cut down through these outwash deposits to the underlying serpentine bedrock.
Hence there are multiple relict channels in Green Valley, and bedrock knolls which were once half-encircled by meanders.
The history of Green Valley has proved elusive, especially the early history, during the Gold Rush itself, and in 1851 and 1852, when fully 2000 people were reported to reside there. Dutch Flat did not exceed Green Valley in population until 1854. Of this early history of Green Valley, I have found almost nothing. Of course there are mines every which way down there, tunnels, shafts, sluice cuts, old camps and cabin sites. And there are old ditches and old trails, often so overgrown with brush as to be impassable.
Gradually I have been GPSing the courses of trails and ditches in GV.
Yesterday, I visited the Tahoe National Forest headquarters in Nevada City, having obtained permission to photograph material in their old "General Land Office" map binders. These huge binders weigh perhaps fifty pounds, and contain, not only the old GLO maps, as old as 1866, which are the first good maps made by the government in this area, but also the various "mineral plats" of patented mining claims.
I was lucky enough to find the plats for the Green Valley Blue Gravel Gold Placer Mining Claim (what a mouthful!), as well as its neighbor to the west, the Williams Placer Mine, both patented, it seems, in 1874. Both mines involve glacial outwash sediments and relict channels.
The old newspapers sometimes call this "Williams Placer Mine" the "Opel and Williams" mine; for, associated with William R. Williams was one George Opel. And later, around 1896, the Opel claim(s) were purchased by a group of investors including the Dunckhorsts; and still later, around 1920, the Dunckhorsts hired one Joe Steiner as their caretaker, in Green Valley. And when one walks down the Green Valley Trail, one usually takes the east fork, near the bottom of the trail, and ends up passing Joe Steiner's grave, at the head of a wet meadow which drops down to a terrace above the river, where a hotel once stood.
From my friends Bernie and Harriet Denton, who spent their summers in GV, as children, in the 1930s and 1940s, I have numerous photographs of GV, and of Joe Steiner, whom they called "Uncle Joe."
The Dentons stayed there with their (real) Uncle Karl, a schoolteacher from Sacramento who had somehow fallen in love with Green Valley. He had a claim at the east end of Green Valley, and a small cabin, with a stone oven. The cabin is long gone, but the oven can still be seen.
Well. I wish I could learn more about the *early* history of GV. Perhaps a concerted effort at those major libraries with collections devoted to California history--the Bancroft, the Huntington, and the CA State Library--would turn up some good stuff.
The very well-drawn plat of the GVBGM shows two ravines crossing the 76-acre claim, Casa Loma Ravine on the west, and Iron Point Ravine on the east. The claim has over a quarter-mile of river frontage, and runs up north away from the river to the line of the High Ditch (the ditch I mistakenly supposed to be a continuation of the GVBGM ditch, which I correctly understood to cross the marble cliffs). Meanwhile, the GVBGM ditch itself runs along about half-way between the river and the High Ditch, and terminates within the claim boundaries.
So, the boundaries of some claims in Green Valley have come into sharper focus.