Saturday, September 10, 2005

Secret Caves of Nevada Point

Early Friday morning I stuffed a sandwich and other oddments into my pack and stared at nothing for a moment, lost in thought: what was I forgetting to take, for a day with Tom Petersen of Georgetown? My GPS unit? The small binoculars were missing from their usual spot on my dusty, broken, old upright piano; then there were the directions to Tom's house, scrawled into my active notebook: a million miles this way, then almost three miles that way: look for a fire station, then a low stone wall ... .

The telephone rang. My wife had a flat tire, right on I-80, just west of Dutch Flat, with three teenagers in the car, on their way to Colfax High. Emergency! So I grabbed the pack and ran the two hundred yards to my car, and whipped on down the freeway a mile or two to where a CHP vehicle already stood guard. My son nearly had the flat tire off, the spare was handy, and in a few minutes they were on their way again, and so was I.

Fortunately I remembered the directions to Tom's place. At last I turned into his rustic realm amid tall pines and saw a curious kind of gypsy wagon, all covered in shingles, built upon a 1940s one-ton truck. Here was a story, many stories. And rocks, hundreds of rocks gleaned from the hills and canyons, nice flat rocks set as stepping stones and little patios, or forming walls. And a nicely crafted house which scarcely looked like a house. A rambunctious young dog kept on leaping up on me and nipping my hands and shoelaces. Tom himself appeared, a sturdy grizzled artist carpenter hiker musician. A lot like me, but as tho some kind of broadening filter had been applied, in the Photoshop of life.

In his house I sipped coffee and admired some really amazing woodwork, in which he had tiled strips of hardwood of different types and colors to make all kinds of wonderful things, tables and chests and piano benches and cabinet doors. This proved to be quite a distraction as I am interested in geometric tilings and want to make some, using hardwoods, in a kind of marquetry process. Tom had already progressed rather fa in this direction. So we talked wood and glue and tools for a while and then climbed into his beat-up pickup for a drive upcountry.

We were aiming for Nevada Point Ridge, dividing Long Canyon, on the north, from the Rubicon Fork of the American River, on the south. This was all terra incognita for me. I had studied my maps and had already deduced that Nevada Point Ridge had a healthy cover of the "young volcanics," as the contour lines revealed a broad, almost flat upland surface between the two canyons, with springs along the sides, surely near the base of the volcanics, surely marking the level of the Valley Springs rhyolite ash.

From Wentworth Springs Road we hung a left on Eleven Pines Road, and dropped into the Rubicon canyon.

We crossed the Rubicon in an area of vertically sheeted granitic rock, on a bridge perhaps one hundred feet above the clear water of the river. A deep pool was just downstream. In crossing the Rubicon we had passed from El Dorado County into Placer County. Two thousand and fifty-odd years ago, Julius Caesar led his hardened veterans of the Tenth Legion south across the Rubicon, which divided Gallia Cisalpina (Hither Gaul; Gaul This-Side-of-the-Alps) from Italy. Civil war followed; but that is another story. However, we sometimes use a similar term here in California: Cismontane California, meaning, California This-Side-of-the-Sierra-Crest.

Climbing up the north canyon wall, we passed a gigantic Canyon Live Oak which Tom said is reputed to be the largest in all Placer County. I said I doubted it, but I can't recall seeing a definitely larger tree of this species.

Very soon we passed from the underlying bedrock, more of the sheeted somewhat mafic granitic rock, into the "superjacent" young volcanics. Since the summit uplands were still high above us this showed that the young volcanics were unusually thick here; at a guess, 500 feet, maybe much more, maybe close to a thousand feet thick, in places. As usual there was no sign of the intervening Valley Springs rhyolite ash; suddenly, we saw Mehrten Formation andesitic mudflows in the roadcuts.

Up on top, we wound through the forest, often heavily logged or even clearcut, and hung a left on a dirt road. Eventually, we came to a gate, which Tom had not seen before, but were able to just drive around it and continue west down the spine of Nevada Point Ridge.

Our first objective was an Indian cave or rock shelter, down by Nevada Point Trail. An archeologist friend had told me about it. We parked at a log deck, on the last bit of intact upland surface at the west end of Nevada Point Ridge.

I should say that, very unfortunately, every other square mile in this entire area was given to the railroad, way back when, and has since passed into the ownership of various lumber companies, notably, Sierra Pacific Industries (SPI). A rich network of ancient trails has been ruined to varying degrees by timber harvests. In fact, I saw almost exactly the same pattern as has afflicted the Big Granite Trail, south of Loch Leven Lakes: an earlier timber harvest, in 1990, first damaged the Big Granite Trail, and forced hikers onto a brand new logging road, before the good old trail with its Forest Service blazes could be regained. Then a more recent timber harvest, in 2004, had added insult to injury, and new damage upon old damage.

The upper end of the Nevada Point Trail has been routed onto a logging road, and within the past two years, a bulldozer has skidded logs directly up and down the historic line of the trail, right past the old blazes, and bladed up a multitude of "water bars," making use of the trail quite difficult.

We abjured the logging road in favor of the newly-damaged old trail, which continues down the narrow spine of the ridge, and, reaching a pass, we held to the south side of things and left the trail, which was dropping steadily towards the Rubicon, instead following a contour around through a nice grove of Kellogg's Black Oak. The crest of the ridge was lost to view above us. We were looking for a line of andesitic mudflow cliffs. First an odd, sunny, barren flat of mudflow was reached, with a scattering of stone flakes, left by the Indians centuries ago. Our cliffs seemed reluctant to show themselves; we dug out Tom's Tunnel Hill quadrangle, and saw that we merely had to exercise patience, and continue wrapping around the south face of the knoll above us.

Suddenly the cliffs appeared, and we reached the cave, at the base of the cliffs, running along almost twenty feet, and eight or ten feet deep, and eight or ten feet high. It was fascinating. The smoke of many fires over many centuries had blackened its roof. The mudflow here was of the "stream-rounded" andesitic boulder type, and apparently the percolation of ground water through this layer had sapped out the length and depth and height of the cave; a stratum of unusually fine-grained mudflow capped the rounded-rock layer, and it was relatively impervious to water, and hence remained more intact.

Boulders of andesite embedded in the mudflow floor of the cave held some mortar holes, some metate surfaces, and, interestingly, some "cupules," which are like miniature, shallow (less than an inch deep), mortar holes. I took some photographs of the plainest cupule, and not until I got home, and looked at this photo on my computer, did I realize that it was part of a faint group of cupules, outlining a partial ellipse.

Such cupules are regarded as a type of petroglyph, and are perhaps more common than is recognized, for they are often faint and blend well with the rock surface. I have seen cupules at a petroglyph site near Yuba Gap, on a sloping surface of glaciated granite, facing up the old Indian trail towards Cisco Butte.

We spent a few minutes at the cave, the only smoke-blackened Indian cave I have ever seen here in the Sierra, before dropping down the steep slopes in search of a spring shown on our map. We found one, not far below, but I was not convinced it was "the" spring we sought.

Striking south at this lower level, we contoured around until we met the Nevada Point Trail at the exact point where it leaves the logging road to resume its historic course. I was shocked and disgusted that the SPI harvest of ~1990 had pushed a road into this steep area, clearly with very little timber to harvest in the first place. What a man with a bulldozer can do, Nature cannot undo for many centuries. And for what? A half-dozen Ponderosa Pines? It is an absurdity and it is, or it should be, criminal.

We chose to skip the road, and follow the historic line of the trail, marked with frequent Forest Service blazes, back up to the ridge crest. It was badly overgrown in places. We lopped some brush and small tree branches away and climbed through various switchbacks until the dread Buckbrush began to appear, in another, steeper, mudflow "barrens," and as I tried to extract this or that thorny branch from the line of the trail, I suddenly realized my left hand was streaming blood. My blue jeans will never be the same. My one pair of blue jeans, forever blood-stained!

Oh well. We forged through more and more buckbrush, doubting after a while if we could even be on the old trail, but a lone large Ponderosa, blazed on both sides, showed we were on track, and we won through to the bulldozed ridge crest. Then a climb of two hundred feet or so, again, stubbornly following the old trail so drastically ruined by bulldozers, brought us back to Tom's truck.

He pulled out a couple of bottles of some excellent home-brewed reddish ale and we rested in the shade for a while.

Then came time for Phase Two, the search for some rumored petroglyphs in Long Canyon.

A certain line of mudflow cliffs on the side of Nevada Point Ridge was adorned by a high and narrow tower of mudflow. Tom pointed it out to me. Rumor put the petroglyphs "near" that tower.

Having just seen a cave with cupules in andesitic mudflow, I was prepared to find another cave, and more cupules; but this seemed wrong, or unlikely: these cliffs faced north, not south, and the Indians liked the sun; these cliffs were high above the meadowy floor of Long Valley; and there was not a speck of the underlying bedrock visible, where one might reasonably expect to find petroglyphs, on some glaciated surface.

We set out cross-country, crossed the dry streambed (there is a deep layer of glacial sediments in this part of Long Canyon, and in late summer, all water flows beneath the surface), and began a steepish climb towards the cliffs through forest logged again and again and again. Brand new "Timber Harvest Boundary" flagging suggested that SPI believes that more than enough logging is not, in fact, enough.

We had some difficult going through patches of water-loving Dogwood which suggested we might be at the level of the Valley Springs fm., but all was masked by glacial till, with many granitic boulders. Finally a small gully offered easy going on up to the cliffs. These cliffs too had many strata of the "stream-rounded boulder" type of mudflow, with intervening layers of fine-grained andesitic ash and sand. The layers were from four to thirty feet thick. The rambunctious dog, Einstein by name, roved above us and occasionally set loose small avalanches of rounded rock whizzing past us. Nerve-wracking. There were many shouts of "Einstein! Come here!", or "Einstein! No!", but nothing could prevent young Einstein from skipping merrily to and fro across the steep slopes above us.

We reached the tower, and saw a hawk, or perhaps an Osprey, soaring just above. The tower was a mere eight or ten feet thick and yet stood maybe forty feet high on the uphill side, and more like eighty feet above the slopes on the downhill side. It was quite impressive.

The varying layers of mudflow were sapped into recesses or projected as overhangs and ledges, according to how much water percolated through each layer. There were a multitude of quasi-caves and ledges we could not see very well, so we scrambled around on very awkward and dangerous terrain, a million marbles of andesite underfoot. We went high and we went low and we went east and we went west.

But no. No cupules, no decent caves, no designs carved into rocks, nothing.

After a good long time up there we retreated down to the valley floor, five hundred feet below, and crossed the once-meadowy floodplain back to Tom's truck, and more red ale.

Shadows were growing long. We drove up Long Canyon a little ways towards Big Meadow, and turned right onto the Nevada Point road, climbing up to the crest, at about 6000' elevation, through much glacial till, and stopping at a fine overlook, with Hell Hole Reservoir below us, and Mt. Mildred, Steamboat Mountain, and various minor peaks along the Sierra crest visible. Steamboat Mountain has a fine set of cliffs of some volcanic rock, perhaps andesitic mudflow, gently sloping to the south; my guess is that the strata composing those cliffs came from the Squaw Valley Eruptive Center, a few miles to the north.

A long drive west brought is back to paved Eleven Pines Road, and we were soon across the Rubicon, and rolled into Tom's place a little after sunset.

It had been a very interesting day in the basin of the Rubicon Fork of the American River.

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