Читать книгу Lens to the Natural World - Kenneth H. Olson - Страница 9

1 / Into the Badlands

Isn’t it astonishing that all these secrets have been preserved for so many years just so that we could discover them?

Orville Wright

The prairies of the West stretch and roll for hundreds of miles. However, in places, the land abruptly falls away. With each rain, channels that are usually dry widen and deepen by eroding the debris of former ages; they all lead, by one way or another, to the Missouri River Breaks. Boulders of the Rocky Mountains disintegrate and mix with the sands and silts of the High Plains in a long but inexorable passage to the Gulf. In the process, strata comprising the skeleton of the earth itself are laid bare, and sunlight falls once again where it has not for millions of years. Such are the Badlands.

These regions in several states were named by the earliest French voyageurs mauvaises terres, the evil lands. To those who lurched toward the setting sun in the wagon trains of the westward migrations, these crumbling terrains were definitely bad for travel, and routes were sought to circumvent them. Beginning in the 1870s, however, crews from eastern universities with their fledgling discipline of paleontology (literally, “the study of ancient being”) were drawn specifically to those scarred landscapes in Wyoming, Colorado, Kansas, Utah, Montana, and the Dakotas.

In 1877, railroaders discovered huge dinosaur bones weathering out at Como Bluff, Wyoming. Ten miles away, fossil bones were on the surface in such profusion that a sheepherder had used vertebrae to build the foundation and part of the walls of his cabin. The dinosaur rush to such regions was on, and excavations at Como Bluff and at so-called Bone Cabin Quarry began to reveal the largest of the dinosaurs: the giants of the Jurassic Period. Collecting on behalf of Yale University, the English clergyman Arthur Lakes documented his fieldwork in a series of watercolors. One painting showed himself and another man clad in parkas and digging in a trench to excavate the great bones, this in the midst of winter with snow banks all around. This laconic inscription was used: “Pleasures of Science.” Thus, the first workers in the field had begun to visualize for the public the hitherto unimagined Lost World of the dinosaurs in the American West.

Today, the desolate Badlands are the Goodlands for paleontology, the science that seeks to reconstruct the prehistoric world from the mineralized bones and other fossils that erode out of such strata.

The sandstone cap-rock on which I am standing provides a view of the banded sedimentary layers extending in every direction. I gaze at the gray, brown, tan, and rust-colored tones, which change with the angled light from morning to mid-day to afternoon. Sitting down on the ledge, I ease off my backpack to pause for a long drink of water and a short lunch consisting of a jelly sandwich. I also blow the dust off the lenses of my binoculars, this in order to better watch a band of showers moving slowly a few miles south. It is rain that has carved these hills.

I swing my legs over the rim and begin to work my way down the slope, leaning into it and steadying myself in the sliding talus with the pick that always accompanies me on such explorations. The wind is blowing, and it takes a moment to identify the location of the sound that halts me in my tracks, tense and alert—that unique, vibrating buzz of a rattlesnake. Its gravel-hued coils lie beneath a sagebrush just two feet away. The forked tongue darts out and in, tasting the air, and the black slits in the unblinking eyes follow my slightest movement. I am the intruder. So, I slowly step away from the sinuous creature, which, today, occupies a hidden and very obscure presence in the western grasslands.

It is, however, a reminder that the Class to which it belongs once ruled the entire earth in what has thus been called the Age of Reptiles. In the air, light-winged pterodactyls soared on the thermal currents with little effort. In the oceans, the waves were plied by huge marine reptiles, some of them as much as forty feet in length. During one segment of time, known as the Cretaceous Period, the waters occupied a shallow basin that went through the heart of North America from the Gulf of Mexico to the Arctic and stretched a thousand miles wide from the rising Rocky Mountains to what is now Minnesota. The boundaries of this sea came and went in transgressive and regressive phases, and, therefore, the sediments it left behind alternate with those laid down on land by rivers, lakes, and swamps. In those latter formations are found the dinosaurs of the Western Interior.

For thousands of years, native peoples had seen the bones weathering out of cliffs and ravines, and their traditions include mythologies pertaining to them, as well as certain observations that anticipated the findings of modern science.

On the return trip of the Lewis and Clark expedition, Clark came upon what he thought was the bone of a large fish embedded in rock. This was along the Yellowstone River, east of present-day Billings, Montana and near a spot known as Pompey’s Pillar. He recorded the event in his journal of July 25, 1806:

Dureing the time the men were getting the two big horns which I had killed to the river I employed my self in getting pieces of the rib of a fish which was Semented within the face of the rock this rib is about 3 inches in Secumpherence About the middle it is 3 feet in length tho a part of the end appears to have been Broken off . . . I have several pieces of this rib.

The specimen is now lost, so it is impossible to confirm its identity. However, given its size and the area in which it was found, there is little doubt the expedition produced the first dinosaur specimen found by a non-native person in the American West.

The first scientific description of a dinosaur fossil was made in 1824 by English clergyman and dean at Oxford, William Buckland. (He was an eccentric, who kept a pet hyena at home, as well as a bear that he often dressed in academic robes to attend university functions.) Buckland’s specimen was a jawbone of a meat-eater that he named Megalosaurus, “large lizard.” Since then, more than a thousand different species of dinosaurs have been studied and named. For more than 150 million years they thrived, multiplied, and diversified as they passed through the sieve of changing environments. And, then, they were gone.

The last of their kind are entombed in the rocks over which I walk in eastern Montana. Layers several hundred feet thick, dating from 65–68 million years ago, comprise the so-called Hell Creek formation. It contains strange “duckbilled” dinosaurs that migrated in herds made up of hundreds and even thousands. Other herd animals included one of the spectacular ceratopsians or “horned-faced” dinosaurs, Triceratops. The skulls of these elephant-sized creatures, in addition to sporting long horns, had bony shields that projected back over the neck. Tank-like armored ankylosaurs lumbered through the bushes. A variety of smaller saurians filled other roles in the ecosystem, including ostrich-like runners that likely fed upon insects and lizards and perhaps rat-sized small mammals. Raptors pursued their prey with sickle-like claws, and, most dramatically, like a huge bipedal caricature of a human being, strode the seven-ton carnivore, Tyrannosaurus rex.

The bones of all of them have been found here. In addition, there were turtles, lizards, and thick-scaled garfish. Crocodiles and alligators bespeak a subtropical climate much like that of Florida or Louisiana today. Unknown then was the winter frost that, today, in the northern part of the continent, cracks and splits the dinosaur bone. Then, there were swamp cypress trees in Montana, and impressions of the fronds of palm trees can occasionally be found when slabs of rock are overturned; abundant fossil pine-cones indicate the presence of towering redwoods. One thinks of the passage in Joseph Conrad’s novel, The Heart of Darkness: “Going up that river was like traveling back to the earliest beginnings of the world, when vegetation rioted and the big trees were king.” In all, a picture is presented of a landscape having lush vegetation and coursed by numerous rivers and streams—a landscape so very much unlike the Badlands of today.

And yet, in the mind’s eye, it’s all there. In the words of naturalist Loren Eiseley, “How often, if we learn to look, is a spider’s wheel a universe, or a swarm of summer midges a galaxy, or a canyon a backward glance into time. Beneath our feet is the scratched pebble that denotes an ice age, or above us the summer cloud that changes form in one afternoon as an animal might do in ten million windy years.”

You can sometimes walk for hours without spotting a trace of anything. Most of what is found consists of bits and pieces of bone that have weathered out long ago; these have deteriorated from the extremes of cold and heat, snow and rain. They do serve, however, as indicators for the most productive zone, the right horizon wherein conditions were right for fossilization. I follow the contour lines of such exposures where these fragments occur. Sooner, or more likely later, I may well find something better, such as one or more complete bones, or—the chances are remote, but best of all—a skull. The trick is to find them at the right time, when erosion has just begun to expose the relic; then, there’s the chance to dig back, reveal, and excavate this treasure of the earth.

This finding represents the intersection of two lines, the chances of which are infinitesimally small. The first one is the path of the dinosaur bone itself, the sculptured form that served function in a dynamic creature and which, at death, is laid down in waterborne sediments. Over the ages, water percolates through the layers and deposits minerals in minute spaces in the bone, hardening and, in some cases, turning it into a stony replica of the original. Millions of years pass, during which thousands of feet of sediment accumulate over it containing other diverse creatures such as the rhinoceros, small horse, giant pig, camel, and saber-toothed cat. Then, the erosion cycle begins, in a process that is still transforming the Great Plains in our day. Down the long reaches of time, the rocks are slowly worn away, until at last, the fossil bone is at the surface once more.

This particular line must now intersect with a second one that represents the appearance on earth of a unique species, this at a time when mental and cultural development enabled recognition of the fossil for what it is. A representative individual arrives at the right time and place, makes the discovery as the bone is exposed, collecting it “in the nick of time,” just before it, otherwise, would be rendered to oblivion by the forces of nature.

As such, the process has always struck me as resembling a picture we have all seen: that of an Alaskan brown bear standing in the rapids of a river as, in one tiny instant, its jaws snatch a migrating salmon from a leap upstream.

That intersection can occur in many places by accident, as dinosaur bones might be encountered when excavating for the basement of a house or in the ditch of a road, turned up by heavy equipment. But it happens most often to fossil hunters, who have come, for just this purpose, to the Badlands.

It’s as close as we are likely to get to time-travel. Simply finding a fossil has a way of linking a person to events and beings of a bygone age. Something then crosses over from eras inconceivably remote to occupy the shattered femur at the toe of your boot or the golden, glistening, and finely serrated tooth in your hand. A connection is created with those vanished eons by a physical fragment: a fossil. Then, one sees the landscape—and perhaps the whole world—in a new way.

Keith Parsons writes in Drawing Out Leviathan:

So Tyrannosaurus rex remains, burning bright in the forests of the Cretaceous night, safely extinct in the depths of time, long, long before our theories could frame its fearful symmetry. Knowledge begins with wonder, and that is the great value of dinosaurs for us, the primal wonder inspired by knowing that such beings once actually walked on the planet . . . We would like to know everything about them, but are frustrated by the myriad of centuries separating us. When we think about the dinosaurs, therefore, imagination must always supplement fact. With creatures as wonderful as dinosaurs, this is the way it should be.

The dinosaurs still exist: in our imaginations and in that stark but sublime desolation we call the Badlands.