William H. Calvin
UNIVERSITY OF WASHINGTON
SEATTLE, WASHINGTON 98195-1800 USA
This page is at http://WilliamCalvin.com/bk3/bk3day4.htm
|The River That Flows Uphill (Sierra Club Books 1987) is my river diary of a two-week whitewater trip through the bottom of the Grand Canyon, discussing everything from the Big Bang to the Big Brain. It became a bestseller in German translation in 1995.||AVAILABILITY limited; the US edition is now out of print. There are German and Dutch translations in print.
The River That Flows Uphill|
A Journey from the Big Bang
to the Big Brain
Copyright 1986 by William H. Calvin.
You may download this for personal reading but may not redistribute or archive without permission (exception: teachers should feel free to print out a chapter and photocopy it for students).
Mile 52AFTER BREAKFAST, Marsha came back from a hike up the beach and reported that there were lots of tadpoles in one of the pools of the creek, amidst the willows and tammies. They were cute, and she offered to show them to anyone who was interested.
"Ah, yes," Alan replied. "We put out a package of freeze-dried tadpoles last night to rehydrate. Nice to hear they're doing so well."
A half-dozen people raised their eyebrows but said nothing (these days, the idea of freeze-dried tadpoles isn't totally impossible). Marsha examined Alan's face carefully for signs of a smile, she hadn't forgotten the split-willow figurine which Alan "found" on the beach. Alan kept a straight face and said that the boatmen also had several packages of freeze-dried cicadas in one of the freezer chests, just in case the bats got too hungry. Alan went on to say that these were special C-minor cicadas, rather than the common cicadas which, he claimed, sing in D-major -- that the bats had been getting fussy lately about their food.
Without a word, Marsha turned and walked down to the boats, grabbed a bailer bucket, scooped up some cold river water, and chased Alan down the beach. The rest of us cheered her on, sounding like a softball team exhorting a baserunner from the sidelines.
Mile 56THE NORTH RIM can be seen from several places along this stretch of river, but only when we pass the mouth of a side canyon. It's hard to believe how high it is. We've been encased by Redwall, and haven't been able to see what's atop it, set back out of sight.
The East Kaibab Monocline has pushed the North Rim up as high as 2,700 meters in places, while the South Rim is more like 2,100 meters high. If we look carefully back up Kwagunt Creek's canyon, we can see one of the highest points on the North Rim towering in the distance. It is more than a mile high from where we are, about the height of a 500-story building. And I thought the Canyon was deep at Navajo Bridge, where a 30-story building would have just fit inside it. That means we've cut 500 stories deep into the earth in just three days on the river. The view doesn't last long, but it is sobering.
Floating the rivers takes you through the land, not merely over its surface. Entering a canyon is akin to entering the living body of the earth, floating with its lifeblood through arteries and veins of rock, tuning your perceptions to the slow pulse of the land, single beats of river current marking the steady rhythmic changes in geologic time. This particular form of intimacy... can only be had on the rivers. It flows through your memory and leaves behind a ripple of emotion: reverence.
........STEPHEN TRIMBLE, 1979
SIXTY MILE RAPID has come and gone. No creek there, just a dry wash. A mere 4, meaning that we held on tight but didn't have to bail much afterwards. We are now seeing patches of the Tapeats Sandstone at river level, which is a sandy brown with lighter patches here and there where slabs have fallen away in recent years.
Alan says that there are several varieties of fossils to be found in the Tapeats, but that he hasn't seen any along the river. We're about to run out of fossils. We are currently in the Cambrian period, laid down nearly 570_million years ago, the age when there was the first big explosion of life-forms in the sea, when evolution really took off. Rocks from earlier than that, which we'll see a little further downriver, have little in the way of fossils because the life-forms themselves often weren't sturdy enough to fossilize.
Presently, as we round a bluff on the left bank, we see a stream of light blue water -- the Little Colorado River -- running down the left side of the river in much the same way as the Paria appeared at Lee's Ferry long ago. We can now see up into the canyon of the Little Colorado River. No rapids. Just two peaceful rivers, gracefully merging.
Alan pushes us over into the bluish waters and then turns the boat around so that he can use a backstroke, rowing upstream into the Little Colorado's canyon. Behind us, another boat rounds the corner and follows us. The side canyon is so wide that we see a good expanse of sky. Back in the Marble Canyon the walls were never far away. And the water -- it is now a pure stretch of the most amazing azure blue. From the morning shadow of Marble Canyon, we have seemingly arrived at a sunny tropical resort.
Little Colorado Confluence at Mile 61, from Leonard Thurman's Grand Canyon River Running web pages.
And this our life
exempt from public haunt
Finds tongues in trees,
books in the running brooks,
Sermons in stones,
and good in everything.
I would not change it.
......WILLIAM SHAKESPEARE, As You Like It, 1599
Mile 61THE AZURE BLUE WATERS are warm and swimmable, not at all like the cold Colorado. We are just a mile upstream in the Little Colorado River, where the waters from Blue Spring flow. When Dan Richard stopped on the bridge over the Little Colorado near Cameron on the drive up to Lee's Ferry, he saw a dry river bottom. When the river runs wet there, these waters run red. Otherwise the Little Colorado's waters flow from some big springs a few miles upriver from here. And we love the blue spring waters.
Little Colorado Confluence
After tiring of swimming, we sat around in the shallow waters talking. Topics such as water color. We have already seen a brief example of the old red Colorado, after the distant rainstorm of the first day. Usually the Colorado is mint green. When the azure blue of the Little Colorado empties into the Colorado proper, it quickly mixes and makes no dent in the colors of Lake Dominy (we have decided that Major Powell surely would not have approved of a reservoir that buried the beautiful Glen Canyon he so admired, and so -- following Edward Abbey -- we call Lake Powell after Floyd Dominy, the chief of the Bureau of Reclamation which created the abomination).
This talk of names led us to discuss what might be an appropriate name for the new, improved Colorado River. "There is already a Green River upstream, and a Rio Verde down south," Dan Richard pointed out.
I reminded them of the other great misnaming by color. "Do you realize that the brain's gray_matter isn't gray at all?", I inquired.
"The gray matter isn't gray?", repeated Abby, incredulously.
"No, not in the slightest."
"Well, is the white matter white?", she asked.
"Oh, yes. The color of porcelain. The white matter's just a bundle of cables, and the white color is from the fatty insulation on the wires. Except the wires are really axons, the long stringy portion of nerve cells."
"So why isn't the gray matter gray?", persisted Abby.
"Because it's red. Sort of reddish-brown. About the color of the river that night after the sandstorm," I ventured.
"Then why was it called the gray matter?"
"Well, it is gray sometimes. In a dead brain. The gray matter's where most of the action is, and that takes a lot of oxygen and sugar. Which means a big blood supply." I sipped my lemonade. "So the region looks reddish-brown when it's alive. Of course, the only people who see it that way are neurosurgeons and neurophysiologists."
"Maybe we ought to rename the gray matter too. But the reddish-brown matter just doesn't have the right ring to it," Ben said.
"How about the Colorado Matter?", ventured Abby. "You said it was the color of the old Colorado River, back before damnation."
We roll that one around a little, taste it, and decide we like it -- the Colorado Matter it is. If anyone asks our opinion on the gray matter.
In our enthusiasm, we even got around to renaming some cities -- for birds that deceive other birds. An aside for those not of the cuckoo cognoscenti: the cuckoo practices parenthood piracy. Cuckoos leave their babies on someone else's doorstep: their eggs in the nest of some other bird species, such as Bell's vireo. Their eggs are speckled, just like those of the vireo; and when the cuckoo hatches, it has a scarlet throat just like the real vireo babies. But thereafter -- ouch! First, the newly-hatched cuckoo chick has a built-in instinct to shove the other eggs out of the nest, thus reserving all the baby food for itself. And does it ever grow! Yet even when it is twice the size of its foster parents, they feed it faithfully. Apparently that scarlet throat is the main way they recognize their young; like the beavers shoving sticks and mud toward the sound of running water, adult vireos have a powerful instinct to shove food at scarlet throats. The cuckoo has successfully imitated that trait, thereby enslaving the poor vireo parents. Hence parenthood piracy. (Who says the scientific literature is dull?)
Now to cities: the Phoenix was a mythical bird whose birth was not your usual event -- it arose fully fledged from ashes. The city of Phoenix also arose unnaturally from the middle of a desert. Not from ashes but from Indian ruins, that being the comparison made by the drunken Englishman who did the naming. It is, however, more like a cuckoo rising from a nest from which Indians and farmers have been pushed out. A city that has fooled its foster parents, the American taxpayers, into feeding it with water and electricity for air conditioning so that it can grow, unplanned, sprawling, over the countryside -- like a cancer, metastasizing here and there by following county roads and turning them into sad cluttered strips, turning cotton fields into tacky subdivisions. Some "developments" look like they will fall into tatters before the mortgage is paid off.
The same might be said of Las Vegas, each of whose gaudy hotels consumes the electricity of a city of 60,000 inhabitants, again subsidized by you-know-who. I suppose that it's probably named for a vega, the Mexican word for a moist meadowland, but we prefer to think that it is named after Vega, the brightest star in the constellation Lyra, whose brilliance is perhaps due to its being a mere 26_light years away -- a near neighbor on the celestial scale of things. Why do we prefer the bright star interpretation? Because silliness has struck again: Vega comes from the Arabic word for the constellation in which the Arabs envisaged a falling vulture.
The brightest star among fallen vultures.... That sounds like Las Vegas, all right. Are you sure that's lemonade in the cooler jug?
Cuckoos are not the only species to enslave those birds with insufficient ways of recognizing their own young: cowbirds do it too, right here in the Canyon, enslaving the Bell's vireo.
As long as we're renaming things, Cowbird would make a nice new name to replace Phoenix. They can call the airport "Cowbird International" instead of Sky Harbor.
We're saving Cuckoo for Las Vegas.
We're not usually this silly. We must be starting to relax.
THE ROCK LEDGES NEARBY are the Tapeats Sandstone laid down in Cambrian times just after the time when life-forms first diversified massively. The surrounding corrugated ledges and overhangs make perfect shelters along the shore if we want to get out of the sun, as we do for lunch. The Little Colorado may lack the underwater life around the coral reefs of the azure Caribbean, but it's rapidly becoming home to us. Some people are still floating in the translucent waters, not even tempted by food. The lemonade tastes excellent, and the supply is endless.
That says something about how much we've gotten into the mood of the river trip. I think we've finally left many of the cares of civilization behind. That may sound incongruous, what with our discussions of science, but technology and science are two separate things to us, as separate as farming and biology. Except for our boats and propane stoves and air mattresses, we've largely escaped obvious reminders of technology. I haven't heard anyone ask what time it is for a day now. We are starting to object when civilization's noisier artifacts intrude, such as the airplanes that fly below the rim of the Canyon. And the motorized boats with their whine and oil haze. I could even do without the Los-Angeles-bound airplanes that crisscross the Canyon at night, winking and roaring across the Milky Way. They can't fly over the White House -- why not ban them over the Grand Canyon too?
Across the river, beneath the overhang of a large Tapeats slab, stands an old prospector's cabin from 1890. Today, it's no more than three walls propped up against the cliff overhang, filled with the usual junk of the last century. Major Powell mentioned seeing some Indian ruins near here back in 1869, but the archaeologists weren't able to find any ruins until they finally tried excavating the prospector's cabin -- he'd evidently improved on the old Anasazi cabin and moved in. There were arrowheads but also split-twig figurines, suggesting that the archaic Indians were here 3,000 to 4,000 years ago.
One of the springs which feeds the Little Colorado is a present-day Hopi shrine, or sipapu. The sipapu is about 7 kilometers upstream from the Colorado confluence. It is a huge travertine dome, built up from the minerals in the flowing water. The Hopi believe that man emerged into this world through this spring. There are other shrines in the area, along a sacred trail leading down to the Colorado River not far below the confluence. The Hopi, who live about 100 kilometers east of here, make ceremonial journeys to collect salt from near the river.
WE'VE HIT BOTTOM WITH THE TAPEATS, at least as far as fossils go, here where the rock is 570_million years old. This is the oldest of the Cambrian layers; everything below it is Precambrian. Cambria is merely the Latin name for a town in Wales which kindly lent its name to the layer. The reason scientists make such a fuss over Cambrian and Precambrian is that the dividing line marks the occasion of a great success story: while some forms of life had existed for over 3,000-million years before then, a great diversity of life-forms seems to have been created by the end of Precambrian times. And these forms had shells sufficient to fossilize. In Precambrian times, the microfossils are as rare as they are hard to see.
We subdivide the animal kingdom into 28 phyla, each of which employ a very different way of structuring a body. Most of them seem to have been present 570_million years ago, when fossilizing started in a big way; that suggests that they may have diversified earlier, but often weren't hard enough to fossilize. Several more phyla seem to have originated during the Cambrian, during the time represented by the Tapeats and Muav layers around here. One of those phyla, the chordates, seems to have arisen from the echinoderms (sand dollars and brittle stars are among its better-known members). The chordates further diversified into vertebrates, into fishes, into amphibians, and into reptiles -- all during the period represented by the layers above us -- and then later into the mammals, primates, apes, and us.
New species were invented all along the way. Most of them died out. There has been a continuous creation of new life-forms as specialized versions of older species have split off. The typical "lifespan" of an invertebrate species within the marine mollusks is about 3-10_million years (though in deep-water species of foraminifera it is three times longer than among the shallow-water mollusks). Then, usually rather suddenly, the species disappears from the fossil record.
Sometimes, superimposed upon this background of individual species coming and going, whole families of creatures became extinct simultaneously. Family? A family is the third of the classification groups; Homo sapiens is in the family of hominids, the genus Homo, and the species sapiens. But a family with only one living representative isn't a good example. How about cats? It would be as if all of the 37 feline species among the carnivora, from lion to domestic cat, had gone extinct together. There are occasions when more than 20 percent of all families of sea-going animals disappear, all within a few million years or so. That is indeed a major pruning of the tree of life; it makes one wonder what happened.
Such an event is called a mass extinction. About nine of them have occurred in the last 250_million years, and probably another dozen during the period covered by the Grand Canyon fossils, between 248 and 570 million years ago. Indeed, they tend to occur at regular intervals, seemingly every 26- to 30-million years or so (the last one was 11 million years ago, so relax for a while).
Two of these mass extinctions have been particularly dramatic. At the end of the Permian period about 248 million years ago, half of the families of marine invertebrates (90 percent of all species) died out within a few million years. At the end of the Cretaceous, about 65 million years ago, a quarter of the families died out, not to mention the dinosaurs. However, the animals lowest in the food chain fared even worse: some 90 percent of the zooplankton (the little microscopic creatures that float beneath the ocean's surface) were wiped out. Of course, that suggests that there wasn't much around for the zooplankton to eat, and since they virtually eat sunlight -- consuming the little plants that do the photosynthesis in the ocean, the phytoplankton -- it may be inferred that the sunlight was blocked for a while. Did a giant cloud cover the earth?
There are various ways of producing such devastating cloud cover. The impact of a large meteor could send a lot of dust into the air. If a dust cloud gets no higher than the tops of the rainclouds -- about 10,000 meters up (33,000 feet) -- rainfall will wash it out of the atmosphere. If the dust (and soot from burning vegetation) gets into the upper atmosphere, it could take several months for such a cloud to clear. Volcanic eruptions, the more frequent generators of such atmospheric disturbances, occasionally turn the sunsets red for a year because of all the tiny particles injected into the upper atmosphere. Temperatures drop around the world, as one can see in the growth rings of long-lived trees such as the bristlecone pine, a tree that grows high in the mountains around here and records faraway volcanic eruptions in the Mediterranean and Southeast Asia. The final scenario resulting in massive cloud cover is called nuclear winter, where cities and forests, consumed in monster firestorms, send smoke particles into the upper atmosphere.
In the search for explanations of extinctions, terrestrial causes such as volcanos and plagues have been suggested, but the betting is on the meteors because the dates of the impact craters seem to cluster around the periods when extinctions occurred. Both craters and extinctions show a recurrence cycle of about 28- to 32-million years. The impact dates for the post-Permian craters cluster right around the dates of the extinctions so tightly that the chance of their accidentally coinciding is said to be less than 0.1 percent. The DuBois family visited the big meteor crater east of Flagstaff before coming on this trip. Jim says that it is over 1,300 meters (nearly a mile) wide and 40 stories deep. This "splash" was made by the impact of an iron asteroid about 25 meters in diameter that punched through the atmosphere about 50,000 years ago, during the most recent ice age. So that's not one of the big ones. But it's very impressive; I can do without anything larger.
While some meteors come from outside the solar system, most are from clouds of ice balls that orbit the sun at great distances, the so-called Oort cloud out beyond Pluto's orbit. A passing attraction kicks them out of their usual orbit and they fall toward the sun; as the sunlight melts the ice and releases gases, sunlight and the solar wind sweep the gas and dust back into a tail -- a comet. Most comets don't come close to us because of Saturn and Jupiter, whose gravity is sufficient to deflect them. A small percentage still make it through to the "inner" solar system. The question is, what could send comets into the inner ring of planets with such regularity that a big impact from one might stir up things on Earth?
One possibility is that the sun is part of a binary pair of stars, the unseen companion appearing to orbit the sun at a great distance in an elliptical path, coming close enough every 28 million years to perturb the Oort cloud and send comets into the inner ring of planets. About 15 percent of all stars surveyed turn out to be binaries, though most are rather closer together.
The sun's hypothetical companion would probably go out into space a distance of 3 light years (our closest known neighbor, Barnard's star, is 4 to 6 light years away) and come in as close as half a light year. This could perturb the inner Oort cloud enough to send a billion comets into the inner solar system during the following 1 to 2 million years, a few hitting the Earth. The long duration of the meteor shower might explain why the dinosaurs took 1-2 million years to die out.
Extinctions seem rather important in the biological scheme of things, as when the mammals got their big chance after the Cretaceous Extinction, thanks to all the niches vacated by the dinosaurs (someone in the next boat remembered the doggerel: "In Cretaceous times the Earth was flat; the fools fell off, and that was that"). The birds and dinosaurs took off just after the Permian extinction. The apes got started after the puzzling end of the Eocene. The rhythm of the extinctions suggests that such major pruning and subsequent blossoming has been a regular feature of evolution for a long time, almost a drive toward more complex creatures. Even if biology were to reach some "balance of nature" (and it probably wouldn't anyway), the comets would stir the pot occasionally, giving newcomers their big chance.
Let's see now. A billion comets in a million years. That would be 1,000 new comets every year coming in from the Oort cloud, so they'd really streak up the night sky like graffiti, possibly preventing a good view of the close approach of the companion star even if it were bright enough. A viewer would see three apparitions per night (creators of ghost stories notwithstanding, an apparition is the technical name in astronomy for the first appearance of a new comet) except, of course, in the year after a meteor hit the Earth, when the dust cloud might spoil the view as well as ruin one's food supply. Those will be exciting times, 17 million years from now. It is likely that the current version of Homo sapiens sapiens will have been replaced by then, but we can hope that we will have an improved descendant species around to see the show. Although, John DuBois suggests, our descendant may be part Homo, part silicon.
If and when the companion star is found, we suggest that it be named Nemesis, after the Greek goddess who relentlessly persecutes the excessively rich, proud, and powerful. We worry that if the companion is not found, this paper will be our nemesis.
.....MARC DAVIS, PIET HUT, and RICHARD A. MULLER, 1984 Proposers, together with DANIEL WHITMIRE and ALBERT A. JACKSON IV independently, of the companion star explanation for mass extinctions
May we not name the sun's potential companion for a figure who embodies [the] central features of creativity in destruction and "neutrality" towards the evolutionary struggles of creatures in preceding normal times? Siva, the Hindu god of destruction, forms an indissoluble triad with Brahma, the creator, and Vishnu, the preserver. All are enmeshed in one -- a trinity of a different order -- because all activity reflects their interaction.... Unlike Nemesis, Siva does not attack specific targets for cause or for punishment. Instead, his placid face records the absolute tranquility and serenity of a neutral process, directed toward no one but responsible for the maintenance and order of our world. ...........STEPHEN JAY GOULD, 1984.
Evolution loves death more than it loves you or me. This is easy to write, easy to read, and hard to believe. The words are simple, the concept clear-- but you don't believe it, do you? Nor do I. How could I, when we're both so lovable? Are my values then so diametrically opposed to those that nature preserves? ...we are moral creatures in an amoral world. The universe that suckled us is a monster that does not care if we live or die-- does not care if it itself grinds to a halt. It is fixed and blind, a robot programmed to kill. We are free and seeing; we can only try to outwit it at every turn to save our skins.
......ANNIE DILLARD, 1974
Mile 64SALT CRUSTS ON THE TAPEATS near the shoreline catch everyone's eye as our boats splash along below the confluence of the two Colorado rivers. These salt deposits come out of the bottom of the Tapeats and, looking like painted waterfalls here and there on both sides of the river, they drip down several stories. They are dramatic evidence of how salt washes out of the earth.
The Great Unconformity
Fritz is telling her passengers about the salt deposits on the left bank, and Alan rows us over so we too can listen. They are sacred to the Hopis, and probably were to the Anasazi as well. A modern-day scientist rediscovered the ancient Indian salt trail leading overland from the Little Colorado's canyon to this site. The salt, which the Hopi call sieunga, is used in ceremonies as well as for dietary purposes. The salt is also found on the stalactites and stalagmites in caves, where it has leached out of the rocks as groundwater percolated through them. Perhaps a solo trip to these sacred salt mines, stopping at each of the shrines along the way, was a feature of the Hopi's "rites of passage" ceremonies.
The trail runs down a platform atop the Tapeats; getting down to the sandy beach is a problem. But once down, a block downriver are the mines, a series of small rectangular holes in the side of the cliff, little larger than picnic baskets, about knee-high above the sandy beach. The sieunga was taken from the stalactites and stalagmites within these shallow caves. The mark of the young man's clan was apparently left above the mine after each journey, and even from the boat floating past, we can see the weathered red and black symbols lining the wall.
As the salt mines recede behind us, the Tapeats ends and a loose red rock emerges along the shores, the beginning of the Dox Formation. Right here, something is missing: more than 250 million years of rock! That's more rock than we have already cut through in order to get to this point. At the bottom of the Tapeats, which dates only to 570 million years ago (the Cambrian-Precambrian boundary), the next rock layer ended 820 million years. The Dox Formation, whatever that is. It isn't that nothing happened for all that time, but the rock it produced was eroded away before the Tapeats Sea started up nearby and swept sand dunes across this region.
Yet another unconformity. The last big one was the gap between the Redwall and the Muav, which we saw yesterday. And while today's 250-million-year gap is usually called the Great Unconformity, there is an even wider 450-million-year gap downstream called the Early Unconformity, representing the period between 1,700- and 1,250-million years ago.
Now, suddenly, the Canyon begins opening up. We are no longer enclosed by two often symmetric walls, as in the Marble Canyon. On our right the cliffs of Redwall are far back from the shoreline and getting even further away as we look ahead. The Dox is soft stuff, easily eroded by the former spring floods. This undercuts the harder Tapeats, and it collapses into the river, bringing with it the Muav, and the Redwall, etc. And so the Canyon widens massively, becoming the Grand Canyon of the Colorado River, the successor to Cataract Canyon, Glen Canyon, and Marble Canyon. The Grand Canyon emerged, thanks to soft rock in the basement.
We can now see long distances. A great wall of cliffs stretches to our left once we pass the salt mines, and the Canyon opens up on the left bank as well. The Palisades of the Desert, they are called, as one promontory after another juts out from the very long expanse of distant cliffs, looking somewhat like the folds in a drapery hanging before a window.
We make a quick stop on the right bank at Carbon Creek to investigate its main attraction, a giant mushroom of a rock. Most Precambrian fossils are microscopic, but this one is several meters across. It is a fossilized clump of algae known as a stromatolite. One can still see stromatolites forming in some hypersaline shallows on the sun-baked Australian coast. I don't know how old this one is -- probably it's Dox age, about 820 million years old -- but stromatolites are among the earliest of known fossils, dating back over 3,500-million years. The individual cells are small, but great mats of them can form, something like coral reefs but without the specialization one can see in corals (which are animals, not plants or single cells).
Things have warmed up back on the river. For some reason -- which I think we're discovering -- this stretch of river is known to the boatmen as "Furnace Flats." The breeze is gone. The sun is high. The river has widened and slowed. The boatmen row and row and row. This is a completely different sort of canyon than we've been traveling through until now.
The Marble Canyon, though lacking marble, is slender and elegant. This Canyon is grand. Despite the heat haze, we can see 30 kilometers, not 5. There are all sorts of seemingly free-standing buttes and pinnacles everywhere. They have names like Vishnu Temple and Cheops Pyramid. Their expanse is mammoth, dominated by the 10 km length of the Palisades. In the Marble Canyon it was like having mountains building up around us. Here we see that we are inside the mile-deep canyon that tourists see from the rim. Indeed, civilization intruding again, we note a little man-made tower atop the southern extreme of the Palisades; Brian tells us it is the Desert View Tower, where admission is charged so that tourists can climb several stories higher, as if the mile depth of the Canyon weren't enough, and had to be augmented with observation towers like those built above the "cannonball" national parks back east. Fritz insists that it is nonetheless a nice piece of architecture.
My fellow river-runners can be subdivided into those that want suntans and those who keep covered up. Covering up is becoming more popular as we gain experience with the river; it isn't that likely to make one even hotter, as desert peoples like the Bedouin of the Sinai Desert demonstrate with their long robes. The suggested packing list for the trip emphasizes "long-shelved shirts" and "long pants, such as surgical scrub pants or pajama bottoms". Short of necessity (and convincing the folks back home that you really went on a trip doesn't qualify), tans aren't worth the trouble and risk (sunburn, dry skin, skin cancer) they carry with them. Back when people only lived four decades, the sun damage didn't catch up with one so often. And here on the Colorado, your suntan oil or sunscreen gets washed off by every rapid, causing an endless cycle of reapplication. It's much easier to wear loose cotton and stay covered up.
Another rapid -- Lava Canyon comes in from the right and Tanner Canyon from the left, all the way down from Desert View. We see hikers who are following a long, 25-kilometer waterless trail leading down here from the South Rim. Tanner Rapid is a good ride, and we get happily soaked, cooling down. Liz, one of the boatmen for another river company with whom I talked back at the Little Colorado, told me she'd hiked down the Hopi Salt Trail in the wintertime, stopping at the great travertine sipapu a few kilometers up the Little Colorado, then continuing over past the salt mines, taking the equally unofficial Beamer Trail on to Tanner, and then up and out by way of the semi-official (but unmaintained) Tanner Trail to Lipan Point, several kilometers west of Desert View Tower. Now that would be the way to spend Christmas vacation.
Row, row, row your boat....
Ahead on the left bank is a hill of perhaps forty stories. There is an unoccupied campsite below it. Ours for the night, happily. Atop the hill we can now see a rectangular ruin, right at the apex of two cusps of the hill's drainages. The red silt hill is capped by a layer of gravel, typical riverbed stuff from the looks of it. Fritz explains that this is an Elston Gravel, the boatmen's name for a geological phenomenon explained by geologist Don Elston, whose theory for the formation of the Grand Canyon explains why there are rounded river gravels 35 stories above the river. The big problem with the straightforward explanation of the Colorado River cutting the Grand Canyon as the dome uplifted -- the theory that Major Powell himself originally put forward -- is that there are some sediments downriver, across Lake Mead, where the river flows over some rock formations only 6 million years old. Over? When Marble Canyon itself is 30 million years old? That's right. First puzzle: the river is cutting into rock a mere 6 million years old. Where did it drain before then? That gets the geologists' attention.
Second puzzle: the Gulf of California didn't open up to the Pacific Ocean until about 4- to 5-million years ago, so where would the river have emptied anyway? Sure, the San Andreas Fault has since provided a convenient opening to the sea for the Colorado River (tectonic plates moving Los Angeles north and all that) but that's very recent. Where did all that water go, back before that? Just dumping it into a pond to evaporate doesn't seem reasonable. Sure, the Jordan River empties into the Dead Sea and the water just evaporates -- but the Jordan River's a creek by Colorado River standards. This is a lot of water we're riding. You'd think that it'd find a way out to sea.
This has led to all sorts of conjecture about how the river might have once come down Marble Canyon and then hooked a left turn into the Little Colorado canyon just like we did for lunch, but continued east into a lake. What lake? The geologists simply postulated one and named it "Lake Bidahochi." It supposedly emptied into the Gulf of Mexico. But there are no Marble Canyon sediments to be found in New Mexico, as there ought to be for that theory to work. Another proposal has the Colorado turning north at the end of the Grand Canyon, draining up into Utah (and then what? Evaporating in the Great Salt Lake?).
Elston, according to Fritz, explains the puzzling 6-million-year-old Muddy Creek Formation to the west by saying that the Grand Canyon and the Marble Canyon were both dry somewhat before 4 million years ago (indeed, the Pliocene climate was quite arid then), with no river to carry away sediments. Nevertheless, erosion continued while the river was dry. The summer sun loosened the cement holding the surface sandstone layers together, so that they continued to erode. Ice and wind in the winter loosened rock, so there was still some spring rockfall. All the loosened rock slid downhill and piled up in sloping terraces crisscrossing the bottom of the dry canyon, covering up the original river bed. There were few flash floods to rearrange the rocks.
Then the climate changed and the Rocky Mountains again sent rainwaters down the Canyon, complete with a dose of river gravel. But over time, the Colorado washed away some of the crisscrossing talus slopes and cut a new channel, leaving lots of new river gravels atop the recent talus. The Elston Gravels. Then the river cut deeper and deeper, finally arriving at the present riverbed, carrying the sediments off to the new Gulf of California and leaving the post-drought river gravel stranded high and dry atop the talus slopes. This scenario would explain the square cut at the bottom of the talus slopes in the Marble Canyon near Nankoweap, and explain why there is river gravel at the 35-story level atop these hills we see on Furnace Flats. And maybe also explain how the 6-million-year-old Muddy Creek Formation got beneath the present riverbed. Correct or not, you can see why river gravels atop that hill behind our campsite are so interesting, the possibilities they raise.
Geologists love such problems, and we too are beginning to appreciate the stories of how this giant four-dimensional puzzle (three plus time) called the Grand Canyon is being unraveled -- though, as Subie observes from the adjacent boat, every theory for the formation of the Canyon seems to be missing a crucial piece of evidence. Such as where the river flowed to, 30 million years ago when the Marble Canyon was surely in business? Or what carved the western part of Grand Canyon? Details, details -- the lifeblood of better theories.
Cardenas Hilltop at Mile 71 with Unkar Delta in the foreground, from Leonard Thurman's Grand Canyon River Running web pages.
Mile 71AFTER THE BOATS HAD BEEN UNPACKED and we had all found campsites in the brush surrounding the sandy beach on the left bank, Jimmy Hendrick asked who wanted to join him for a quick trip across the river to see the Anasazi ruins at Unkar Delta. I think that Jimmy hasn't had enough exercise today. He got a half-dozen takers despite the domesticity engendered by setting up camp, and he rowed us across the river. We were carried a bit downstream, of course, and we'll have an upriver stint to do when we return. After Jimmy tied the mooring line to a rock, we clipped our life jackets to the boat rigging and set off to hike the rest of the way down the right shoreline.
This 10-mile stretch of river, with its frequent sandy shores and open low hills, has more Anasazi ruins than any other. While the Anasazi may have lived here because it was easy to reach, old Indian trails have been found all over the Canyon, some leading to cliffs that no modern-day hiker will tackle. I think their skills exceeded ours. Furnace Flats probably was popular because the Anasazi could grow crops such as maize (corn), beans, and squash close to the river. Only a few more miles downriver the rock walls close in again, at the Granite Gorge.
There is a new dig just across from our Cardenas campsite, but most of the Anasazi ruins are two miles downriver, next to Unkar Rapid. There is a big "delta" where Unkar Creek opens out, a broad plain around which the river hooks. The delta is now several stories above the river, with a channel cut through it for the present course of the creek (actually it is not a true delta formed by the creek, but instead river gravel and the like which the Colorado has piled up here, perhaps because a bottleneck once choked off the river a few miles downstream from here). The pseudo-delta has pushed the river to the left against a high cliff of some 30 stories, cut into that hill up behind our campsite at Cardenas, the one with the ruin atop it.
While some Anasazi lived here briefly about A.D. 900, it wasn't until 1050 that Unkar Delta was inhabited again. They would have seen the 1054 supernova rising right over those cliffs across the river above the rapid. And then, between 1064 and 1067, they would have seen the eruptions of the Sunset Crater volcano about 50 kilometers south of here, which would have darkened their southern sky. In 1066, Halley's comet would have lit up the night sky, just as it did for the Normans invading England. An exciting time for the people here at Unkar.
The rainfall always varies from year to year in the Grand Canyon, some years getting ten times as much as others. The longer-term rainfall trends seem to have been important in determining whether the land could support the people. Judging from the tree rings, the years between A.D. 1050 and 1070 were exceptionally wet years all over this area. An Anasazi population explosion ensued, with new settlements springing up all over southern Utah and northern Arizona during this period; a few families settled at Unkar Delta. Then a drought hit between 1070-1080; what happened to Anasazi population numbers is unknown, but many of the baby-boom generation or their children must have starved. Unkar was deserted. Unkar Delta was resettled in 1080 by a larger population, perhaps ten families since ten hearths have been found. Drought again caused the abandonment of the Delta between 1090 and 1100. The final period of Unkar habitation occurred between 1100 and perhaps 1130, the beginning of a long dry period.
From this, one might get the impression that opportunity created by rainfall attracted Anasazi to live in the Canyon year-round. However, the rainfall at Unkar Delta during the corn growing season probably produced no more than half of the water necessary for that crop; irrigation of some sort seems likely. Of course, the Anasazi were still hunting. Nearly half of the bones found here are from rabbits and hares, and most of the others are from bighorn sheep. That there are hardly any deer bones to be found suggests that the inhabitants weren't hunting much up on the rims and hauling the carcasses home. The bighorns live in the canyon, but have to come down to seeps and waterholes in the side canyons for water; there are many places in Unkar Creek where they could have been easily ambushed by Anasazi hunters. And the Anasazi were surely still gathering beans, fruit, and seeds from inside the Canyon. The edible prickly-pear cactus grows everywhere on Unkar Delta and the surrounding deserts; mesquite trees with their beans are also here. But mainly, the Anasazi were growing corn, squash, and beans wherever there was water nearby.
Unkar Delta is breathtakingly beautiful, with a spectacular setting deep within the Grand Canyon. But the beauty seen by the contemporary visitor may not have been appreciated in the same way by the prehistoric farmers who occupied the delta, for the canyon would have been a demanding environment for early Indian agriculturalists, allowing little time for aesthetic contemplation.Jimmy showed us the pueblo-like apartment buildings, row houses of two to seven rooms facing a subterranean ceremonial room called a kiva that was probably in use on such occasions as the full moon we'll see tonight. In the 1080-1090 group of buildings there were two kivas, one dug into the earth almost 2 meters deep, the other barely a meter deep and of quite different construction; this makes one wonder if the ten families included several different subcultures that required different religious housing. Or if there were a lot more families, but some built where the floods have erased their traces.
.......the archaeologist DOUGLAS W. SCHWARTZ, 1980.
The group that came after A.D. 1100 were less addicted to linear row-house construction, and tended to construct complexes of living and storage spaces -- but again, probably no more than 10 families lived here. They had only one kiva; none of the kivas were circular as was the fashion over in Chaco Canyon, all were square or oblong.
The North Rim towers 500 stories above us in the western sky, Cape Royal being the most obvious landmark. There is a triangular gap in the topmost cliff, where blue sky can be seen through a giant hole in the rock. This is Angel's Window, and we could probably see tourists standing atop it if we had brought the binoculars along. From up there I once saw Unkar Delta spread out below; I could even follow the course of Unkar Creek as it descended the side canyon. The Anasazi had a string of settlements along that creek. Starting several miles up from the delta, there are seeps where willows and even cottonwood trees grow. A series of twelve granaries and twenty rooms have been found so far, many in the upper reaches of the creek just below the Redwall cliffs. From Angel's Window I could look down 300 stories and see the cottonwood grove around which the Anasazi farmed in upper Unkar Creek.
Some Hopi-style pottery was found here on the delta, dating from about A.D. 1300, but in quantities and locations which suggest that the Hopis were just passing through on a trading expedition. That, together with the Hopi's creation myth which says that they arose from the sipapu up the Little Colorado's canyon from whence the azure waters flow, is part of the circumstantial evidence that says the Grand Canyon Anasazi are indeed among the Hopi's ancestors.
The obscure moon lighting an obscure worldWE NAPPED AFTER DINNER for a few hours and then arose for a quick cup of coffee. Some people turned over and went back to sleep. "Seen one eclipse, seen them all," someone said. The full moon was up, judging from the way the canyon walls to the west were illuminated, but it was out of sight behind the hill that had the ruin atop it. After a second cup of coffee we set off on a trail that led out of the back of the campsite and continued right around the hill we'd seen from the river.
Of things that would never be quite expressed,
Where you yourself were never quite yourself
And did not want nor have to be....
.......WALLACE STEVENS, The Motive for Metaphor, 1943.
Flashlights, as usual, were discouraged by the boatmen, who believe in the virtues of dark-adaptation, and so the group of us went in serpentine fashion along the switchbacking trail that led around and up the hill. It looked exactly like that moonlit hillside scene from the classic Ingemar Bergman movie of the nineteen-fifties, The Seventh Seal, where Death is leading off a long line of his victims along the skyline. And soon the leader of our line, a boatman named Howie Usher (who can best be described as the living incarnation of the character Zonker Harris in the Doonesbury comic strip), was furnished with an appropriate scythe-like stick to carry. He already, for reasons known only to himself, had a white bedsheet draped over his head and flowing as a cape.
Unkar Rapid at Mile 73, seen (in daylight) from the Cardenas overlook, from Leonard Thurman's Grand Canyon River Running web pages.
Around and around, up and down we went. Lots of moonlight, though there's already a nick taken out of the side of the moon. After about half an hour, we arrived at the top of a cliff overlooking the Colorado River at Unkar Rapids, Mile 72. Laying down to peer over the edge, we not only saw but heard the great rapids pounding away about thirty stories directly below. Moonlight. In the bottom of the Grand Canyon. Looking down at a great, long rapid and feeling its roar.
Howie disappeared somewhere. Soon, from a promontory somewhat above us and a short way downstream, there issued an Independence Day sparkler, thrown in a great bright arc out over the cliff and eventually winking out in the rapids below. Subsequently, holding a second sparkler out in front of himself, Howie came running down the slope toward us, white cape flying behind him and illuminated by the sparkler. A strange apparition, in both senses of the term. But even without the embellishments, the Unkar cliffs provided a majestic spectacle with the light of the full moon and the sound of the rapids.
The Anasazi living on the delta would have had a spectacular view of burning objects thrown off these cliffs. As we saw this afternoon, these cliffs towered above them like a row of skyscrapers above an inner-city park. Where we were lying had probably been the site of ceremonial bonfires in which burning coals were pushed over the cliff. This is, of course, all conjecture; but if one were an Anasazi shaman, it would surely be too good a spectacle not to utilize. Ancient fireworks. They probably made the same "ooh-ah" sounds that we made in response to Howie's sparkler.
BESIDES THE SPECTACULAR CEREMONIAL SITES all around them, one has to ask why the Anasazi bothered to farm in the bottom of the Grand Canyon. They were undoubtedly attracted to the Canyon's bighorn sheep and rabbits, edible cactus and the beans of the mesquite. Long before the Anasazi settled here, their hunter-gatherer ancestors surely visited the Canyon regularly for such things. The Canyon bottom would have attracted them with its long, almost frost-free growing season. It can be snowing on both rims without any snow falling near the river itself, a mile below -- just as one February morning I once drove from Jerusalem down to Jericho, and in 30 minutes went from snow at the ridge of the Judean Hills to orange blossoms near the Jordan River and Dead Sea. We're used to thinking that it's colder up in the hills, but we're often surprised when it's warmer down in a valley.
I wandered off to look at other views in the fading light, and I got to thinking. Back before farming, when hunter-gatherer bands were wandering around the southern Colorado Plateau, they probably had to migrate south -- down toward Phoenix -- for the winters. It's just too cold above 2,000 meters elevation. Once agriculture started down in the southern valleys (it spread north from Mexico), there would have been population pressures: too many people living down there year-around who also wanted to hunt in the winter, competing with the seasonal visitors. I'll bet that as a result, the pre-farming Anasazi started congregating right here: instead of going south for the winter, they descended into the warmer bottom of the Grand Canyon. The bands probably were small -- less than twenty-five people. And so eligible marriage partners were likely to come from another band. Winter was probably the marriage season. So farming here at Unkar Delta might have been just the outgrowth of an old tradition of meeting here in the winter.
From up atop the Cardenas cliffs, we could better see the obvious places to farm on the delta and explained the Unkar Anasazi story to those who hadn't taken up Jimmy's offer to row across in the afternoon. The Unkar Anasazi spread up the creek as far as possible, we mentioned, using every spring or seep to grow food. But, as Barbara noted, there isn't as much sunlight back up the creek year-round, given the long winter shadows. And it got colder as the Anasazi went higher up the creek.
The problem is even worse when farming the North Rim itself, which towers a mile above Unkar Delta. No problem finding lots of land up there on the Walhalla Plateau and elsewhere, but snow would have been a limiting factor. Warm as it remains on the Canyon floor during the winter months, the North Rim is usually buried under several stories of snow from October to May. There are only about 102 days free of frost up there, which poses a severe problem. Judging from present-day Hopi corns, it takes about 120- to 130 days for a crop to mature. Plant a week too late and the autumn frost would come when the corn was still immature, lacking all that substantial late growth.
Since the winters are pretty severe up top, those people likely went south for the winter -- about 8 kilometers south, back down to Unkar Delta. After the snowmelt the Anasazi went back up there to plant crops and repair their summer homes, maybe clearing some more forest to create more planting space, to let in some more light. I suggested that they could have carried starter plants up from their open-air hothouse on the Canyon floor. That forest floor is good soil, far better than anything in the bottom of the Canyon, where the ground is often too alkaline and nitrogen-poor. And it rains regularly in the summer up there, as the monsoon clouds form at lower altitudes and are then pushed higher as they are swept toward the North Rim, cooling and losing their moisture over the forests.
And as Dan Hartline then pointed out, they could also have carried soil downhill, improving their sandy plots near the river with some good soil from the forest floor atop the North Rim.
The tight growing season suggests that the Unkar Anasazi badly needed an accurate calendar. While they could have planted a staggered series of crops in the bottom of the Canyon, they'd have needed something more than the improving weather to tell them when to plant higher up the trail, and on those terraces atop the North Rim.
The moon's cycle is, of course, one of the most tempting calendars --"we'll meet there when the moon is full," etc. But errors accumulate; year-round, counting the number of full moons is no better than sniffing the air on the first nice day of Spring -- because 12 lunar months is about 11 days short of one solar year, so that a moon calendar quickly falls out of synchronization with the seasons. This didn't keep the Egyptians, Romans, and many others from attempting lunar-based calendars. Moreover, correcting the calendars after they drifted away from the seasons surely aided the development of mathematics (as one can see down in Mexico, where the Mayan 260-day ceremonial calendar meshed even more poorly with the 365.24-day length of the solar year and the seasonal cycle). And 11 days is a serious error when, as at the North Rim, one's growing season is less than 102 days long.
It makes you wonder how they did it. Marginal agriculture gets humans into solving some interesting problems. It's not like hunting and gathering.
It is a mark of modern ignorance to think that we have become progressively smarter.... Who is to say whether the task of tackling a problem without the benefit of a well-developed body of methods and information may not have required far greater intellectual vigor and originality than is needed [today] for proceeding from problem to problem within the safely established disciplines? Prehistoric, early historic, as well as medieval science have faced such a task.
......the historian THOMAS GOLDSTEIN, 1980
AND MEANWHILE, BACK ON THE LEFT BANK, we watched the moon being eaten up to the accompaniment of the roar of the rapids. This cliff is one of those special places, a natural spectacle that suggests human ceremonies. I was reminded of when I first saw Delphi, near the top of a steep-walled Greek valley which opens out to the sea. One stands there looking out, the wet cliffs behind one -- a real feeling of being perched on the edge of the universe. Especially when the springs which made the cliffs wet were emitting steam. A perfect setting for an Oracle. And temples.
Besides the ruins on the right bank which we saw earlier, there are ruins over on this side of the river too. A particularly enigmatic ruin is on the hilltop up behind our campsite, the rectangular one we saw from the river as we arrived. By the time that the moon had lost a big nick out of its lower left rim, Alan asked who wanted to go up to the ruin and watch the eclipse for a while longer. About six of us decided to go and started out. There was plenty of light for picking our way cross-country up the hill, then walking along a high ridge which led to the hilltop.
The rough walls of the ruin, which we could see in the fading moonlight, stand less than chest-high, and are made of piled-up rocks. No mortar. No sign of a roof. It seemed like a single room of house-trailer dimensions, almost 4 meters wide and 9 meters long. The second Powell expedition discovered this hilltop ruin in 1872. People were around here about the year A.D. 1100, to judge from the pottery styles found nearby, but otherwise the ruin is undated. It is not a sensible place to live, far from the water and exposed to the winds, but it has a spectacular view up and down the Canyon, a panoramic skyline. Was it perhaps a lookout? A guardpost? A temple, perhaps an above-ground kiva?
We explored the hilltop and caught the expansive view back upriver toward the Hopi salt mines. The Palisades were all spread out to the east, but the view was fading, the moon now down to a crescent. So I settled down on the southern slope of the hilltop ridge, facing the disappearing moon, hands behind my head, and looked up at the canyon walls and the sky. You'd think we would be sleepy, but no -- everyone's wide awake with the excitement of this place. There's a gentle breeze blowing through the darkening night, freshening our faces.
As I took in the view and wondered why they had built here, another possible use for the ruin occurred to me. This would have been the perfect place for the Unkar Delta people to keep a calendar for their agriculture. The position of sunrise on the horizon provides a simple calendar, requiring none of the fancier knowledge of astronomy ascribed to the builders of Stonehenge (and a simple seasonal observatory is surely how they, too, got started). Each morning in winter and spring, the sun rises further north. Then, at the summer solstice, the sunrise turns around and heads south again.
One can use that horizon calendar scheme almost anywhere on earth, as long as the horizon is subdivided -- mountain peaks work nicely as markers -- and one has a customary point of observation, such as a favorite hilltop. I examined the eastern skyline in the moonlight. The most prominent landmark is the Palisades of the Desert, that expanse of canyon rim where the Kaibab, Toroweap, and Coconino layers form a vertically scalloped cliff, extending from northeast down to about due east. A regular series of promontories stick out, like columns on a Greek temple. That's where the sun would rise all through the spring and summer. No trouble with giving those promontories names, just as we name the months. I counted the number of notches in the skyline as best I could in the fading light, and decided that between the approximately due-east sunrise of the spring equinox and the northeasterly sunrise at the summer solstice, the sunrise position would traverse at least a dozen easily identifiable markers over that three month period. One every week, on the average.
Then I looked to the southeast. I couldn't see the South Rim because of a large butte inside the canyon, obscuring the view. It seemed no more than a few kilometers away and rose up rather high in the sky, meaning that sunrise in the winter must have been pretty late [9:14 A.M., I discovered the following winter, but that little expedition is another story, told in my book How The Shaman Stole The Moon]. The winter solstice sunrise, I mused, must come up over that butte somewhere -- maybe in that nice V-shaped notch? [Not quite: if we stood in exactly the right place, it first peeked through a hole in the cliff, looking like a brightly illuminated eye in the profile of an Indian chief].
So that's where the sun turns around -- if one prays hard enough. The winter solstice occurs during the Hopi's high religious festivals, I remembered from a display at the Museum of Northern Arizona just outside Flagstaff. For at least a week or so, the position of sunrise would change so imperceptibly that it would seem to stand still on the horizon. Then it would slowly begin rising somewhat farther north each day, reaching the Palisades by spring and then continuing through that series of notches during the springtime. Each one of those notches on the Palisades could mark a time to plant, the earliest ones for the lower elevations, the later ones in May -- such as that big promontory with the finger projecting from it, Comanche Point [the sun rises there on 30 April, it turns out...].
I was feeling very pleased with myself. It felt distinctly extraordinary, as if I were rediscovering how the Anasazi thought a thousand years ago. Not merely as if I were slipping into their frame of mind, but as if I were glimpsing one of the ways in which our even-more-distant ancestors got started doing science.
The last sliver of white disappeared from the upper right edge of the moon, and suddenly the Canyon seemed much darker, the moon dusky (the reddish glow from all the sunlight bent and scattered by the Earth's atmosphere into the shadow cone). And the stars much brighter, Milky Way and all. But I could barely see the Canyon rim, my calendar. I settled down again, hands behind head, and looked up at the skies.
WE WERE GETTING IMPATIENT, awaiting the end of totality, trying to guess when the first signs of sunlight would again appear on the shadowed moon. And always guessing wrong. I was reminded of when I was a child, being impatient when the family car was stopped at an endless traffic signal, wanting the red light to change to green. And then my father would command the traffic signal to change -- all he had to do was wiggle his ears.
Once I knew of his magical ability, I would always demand that he make the signals turn green. He would usually demur, but would finally yield to my pleadings to wiggle his ears. And sure enough, the signal would promptly turn green. I was amazed. Not being able to wiggle my ears myself, I was frustrated that I could not command the signals. It took some time before I discovered for myself his trick of watching for the green to change to yellow on the cross-street's traffic signal -- my very first scientific triumph. But I never did learn how to wiggle my ears.
Eclipses weren't merely mysterious in the good old prescience days -- eclipses were magic. High drama. To some peoples an eclipse was probably the harbinger of the end of the world. Anyone who could manipulate an eclipse, or seem to do so, surely reaped whatever rewards a society had to offer. It would, of course, have been an impressive performance if an Anasazi shaman could have ordered the end of the eclipse, successfully commanding the reappearance of the lost moon by performing a brief ceremony before anyone else could detect that totality was almost over. But, hard as we tried to guess when our eclipse was ending, we kept guessing wrong. Still, the shaman's tradition probably told him that eclipses didn't last forever, just an hour or so. The shaman could start up his "ear wiggling" ceremony after a while -- one can always stretch out a prayer -- and sure enough, pretty soon the eclipse would start to end. It would probably convince most of his naive audience -- not being so well advised by tradition that eclipses always end after a little while -- that his magic was powerful.
Still no sign of sunlight on the moon. It remained a dusky red orb, an unnatural disk in the starry vault of the heavens.
Of course, predicting the start of an eclipse would be an even neater trick. To do that, you've either got to have detailed records in the manner of the Mayan astronomers down in Mexico, or you've got to watch both sun and moon carefully and apply some simple rules. The Anasazi certainly became sophisticated about sun and moon cycles over in Chaco Canyon. A pair of spiral pictographs, much like the petroglyphs we saw pecked into the rock slab back up at South Canyon, serve to track the annual sun cycle as well as the 18.6 year moon cycle. It's not very accurate -- you'd do better watching sunrise on the horizon to determine the solstices -- but it demonstrates that the Anasazi knew about the moon movements on the horizon. Not bad. If the Anasazi attained such sophistication (probably in the years between A.D. 920 and 1130, when the finest architecture and road-building took place at Chaco), what simpler methods were in use out on the agricultural fringes of their civilization, such as here on Furnace Flats?
[Well, to my surprise, they were pretty sophisticated here in the "wilds," predicting both solar and lunar eclipses by a method simpler than Stonehenge's. No counting, no records needed -- just the Palisades of the Desert: they measured the moon's movements with the sun's ruler but restarted their calendar names every half-year ("January" and "July" were called by the same name in the historic Pueblos). You wouldn't think that you could predict eclipses with just those two practices and no records, but you can -- and the Anasazi did. The simple rule: whenever the sun's date is almost the same (or at least has the same ambiguous name) as the moon's "date" (read off the sawtooth horizon calendar as if the rising moon were the sun), watch out for an eclipse! Tune in next time for another exciting episode in Anasazi astronomy -- and find out why such often-inaccurate eclipse warnings and the frequent partial eclipses probably persuaded the ancient peoples that prayer was powerful, that it could deflect the moon from its normal path, preventing it from being consumed by sky monsters.]
Still no sign of the end of totality. I had half a dozen false alarms, thinking I'd seen a sliver of sunlight on the right side. And I was getting sleepy, even though we had been vigorously discussing how the earth and moon were formed out of the primordial dust cloud. Alan said that maybe we should head back down anyway. So I got up onto stiff legs. Walking in total starlight? But I just followed the leader, my feet telling me when I strayed from the path -- the loose stones all seemed to have been kicked off the trail by previous hikers, so the true path felt more comfortable for walking. No sooner did we get down to the cliff overlooking Unkar than the first sliver of light appeared on the moon, considerably brightening our path. We couldn't find any moonwatchers at the cliff; they'd evidently all gone back to camp long ago. So off we went, on a real trail and with the light getting better and better. At one point I looked up at the Palisades and remembered that the Unkar Anasazi would have seen the Crab Nebula supernova rise up there. And I wondered if they marked the spot where it rose in some way -- whereupon I promptly wandered off the trail and stumbled into a small prickly-pear cactus. So much for that train of thought.
By the time we arrived back at the silent camp along the riverbanks, we had almost half a moon. We virtually ran the last downhill section of trail, it was so easy. I think that the Anasazi must have gotten around pretty well without flashlights.