Читать книгу Lens to the Natural World - Kenneth H. Olson - Страница 10

2 / Stories in Stone

Fossils

And this our life, exempt from public haunt,

Finds tongues in trees, books in the running brooks,

Sermons in stone, and good in everything.

Shakespeare

Fossils may be defined as any material trace or evidence of prehistoric life, and they are of numerous sorts.

Most abundant are the shells of marine invertebrates, such as clams, oysters, and snails, wherein the shell is very little altered from what it was in life. A fossil may consist of a piece of mineralized bone, the flattened skeleton of a fish, a single tooth, or the carbonized imprint of leaf from a long-vanished forest. Insects, complete to the smallest detail, are locked in amber, once the flowing sap of pine trees in which they became entrapped. Tracks left by dinosaurs or other creatures on some damp beach have hardened into a stony matrix and represent, in a sense, the fossilized behavior of the animals that made them. (It is said that many years ago, a prospector notified a university about dinosaur tracks that he had found. He sent a photo of one on a thick slab of rock, which he had dug up and weighed. “Think of the size of the great dinosaur that made this wonderful track,” he wrote. “Think of how big he must have been in life when just one of his footprints weighs 562 pounds!”)

In any case, many of these objects can be rather easily recognized, and one can say, “Here is a fossil; it is something of a creature from the distant past.”

Photographic editor Frances Schultz has written: “The past survives only on average. A tiny fraction of all dinosaurs fossilized; a tiny percentage of all photographs survive. This is as it should be, or we would be knee-deep in bones and Kodak moments.” Nevertheless, fossils are found in some abundance, even amid the stone, steel, and concrete canyons of New York City. In a stroll around Manhattan, you can see fossils from other continents, as well as from several regions of the United States. Limestone, largely made up of small marine creatures, was a widely used building material in the last century, and such stone from Indiana sheathes the Waldorf Astoria and the Empire State Building. Some of the highly polished stone on building facades is limestone that, over the long reaches of time, was metamorphosed by heat and pressure into marble. The lobby of the Tishman Building on Fifth Avenue is finished in what the building trade calls “French rouge antique,” a red limestone that was laid down in the bottom of the ancestral Mediterranean Sea some 360 million years ago. In the walls can be seen various fossils of shelled creatures of the time, many of them coiled and chambered structures built by ancient relatives of the living squid and octopus. At Saks Fifth Avenue, the yellow-colored rock framing the doorways consists of slices through a fossilized reef built by corals. At Tiffany’s, the glittering diamonds in the display window are also encased by fossils, this time of crinoids or sea lilies, ancient relatives of the starfish and feather stars. In the Roosevelt Rotunda at the American Museum of Natural History are 100-million-year-old clams in a decorative limestone from Portugal. In Rockefeller Center, the huge lobby of the RCA building is covered with a near-black stone mottled with white snail shells and other fossils that were laid down in a tropical sea 475 million years ago. Those dark slabs came from quarries on Isle La Motte in Lake Champlain in Vermont, and such stone was also used in the Metropolitan Museum of Art.

In our bedroom is an antique washstand from England. A close look with a ten-power magnifying glass reveals that the polished gray marble top is studded with the intricate structures of ancient corals.

However, recognition of this sort did not come easily to our ancestors. It is true that some of the Greeks of ancient times had a general sense for the nature of these things. Philosophers and historians of the day, such as Aristotle and Herodotus, noticed that marine forms could be discovered far inland and drew the proper conclusion that the sea had once occupied those locations. Ovid of Ancient Rome wrote, “Nothing lasts long under the same form. I have seen myself what was once firm land become the sea; I have seen earth made from the waters, and seashells lie far away from the oceans.”

Such knowledge was largely forgotten in succeeding centuries. During the Middle Ages, a popular view was that fossils “grew” in the rocks, much as crystals do. People spoke of the vis plastica or “plastic force” that fashioned various shapes, many resembling living animals. Unknown seeds were thought to germinate within the rocks to create the objects, or they were explained as having been triggered by “emanations” from the stars. An alternative explanation attributed fossils to the biblical deluge of Noah.

The term “fossil” was coined by Agricola in the sixteenth century. At that time, it simply meant any curious object that was dug up and could refer to odd-shaped rocks and to cultural objects such as arrowheads.

Gradually, a more accurate understanding spread, this in consequence of the growing inclination to distrust mere authority in matters of natural history and, instead, to favor first-hand experience and observation. Petrus Serverinus, a sixteenth-century Danish alchemist, advised: “Go, my sons, burn your books and buy stout shoes, climb the mountains, search the valleys, the deserts, the seashores, and the deep recesses of the earth . . . observe and experiment without ceasing, for in this way and no other will you arrive at a knowledge of the true nature of things.” Passages in Leonardo da Vinci’s Notebooks indicate he realized that shells found in the mountains were from ocean sediments that have been elevated to such heights over long spans of time. Nearly two more centuries were to pass before such insights would have a much wider audience.

Fossils inform of creatures and environments of the remote past. In addition, some are beautiful. Upon being shown a trilobite, most people are fascinated by the symmetry of its segmented body and by its many-faceted eyes set in stone. The rainbow hues of light refracting in the layers of an ancient cephalopod’s smooth shell entrance every eye, and the thin, lace-like lines that separate its hollow chambers are simply exquisite.

The Information Age, with its preoccupation with numbers, computers, and quantitative analysis, leads some to shy away from aesthetic pleasure as a part of science. Yet, a real part it is. Princeton researcher Glenn Jepsen wrote this passage some five decades ago: “As the successive layers of matrix are cleaved away to expose a petrified bone of a carnivorous dinosaur, a paleontologist may thrill to see it as a beautifully formed organization of elements that have served many functions in earlier eons.”

In the first volume of the recent biography of Darwin by Janet Browne, Charles Darwin: Voyaging, the author relates that as a young man Darwin was, in his own words, “an idle sporting man.” His father was more emphatic: “You care for nothing but shooting, dogs, and rat-catching, and you will be a disgrace to yourself and all your family.” However, by the time he was sailing around the South American continent on the HMS Beagle in 1833, he had been captivated by the stories in stone he was learning to read. “I wish any of you could enter into my feelings of excessive pleasure, which Geology gives, as soon as one partly understands the nature of a country,” he exclaimed in a letter to his family. “There is nothing like geology: the pleasure of the first days partridge shooting or first days hunting cannot be compared to finding a fine group of fossil bones, which tell their story of former times with almost a living tongue.”

George Gaylord Simpson, one of the twentieth-century’s foremost paleontologists, shared this enthusiasm: “To those who follow it, the pursuit of fossils is more exciting and rewarding than the pursuit of living fish, flesh, or fowl. It has all the elements of skill, endurance, suspense, and surprise; and the resulting trophy may be a creature never before seen by man.”

Clues to previous worlds, the intriguing form and image of the fossil itself, and the adventure of the pursuit: those are reasons enough for some to engage in this endeavor. However, there is at least one more reason—and this is an intimate one—for every person to have an appreciation for the subject: it has to do with the fact that the earth recycles everything. In fact, this aspect of the story begins even before the existence of the earth itself. Astronomers and physicists have expanded the tale to include the idea that the iron in our blood and the calcium in our bones were formed in the interior of stars, the only place where temperatures are reached that are high enough to create the heavy elements of the periodic table. Then, such elements were scattered into space by the unimaginable force of a supernova explosion, the debris of which was swept up into the orbit of the next generation of newly-formed stars, enriching their planets with the building blocks of life and eventually producing creatures compounded of dust and the light of a star.

Each time an animal dies, its decomposed constituents are sent back into the cycle, “dust to dust, earth to earth, ashes to ashes.” So it has always been. And that means, among other things, that we are part dinosaur.

Suppose we had a piece of toast for breakfast this morning. The chances are good that the wheat from which the flour was made was grown in the middle western states. The plants now cultivated and harvested there are constituted by minerals in the soil, soil that once made up sediments of ancient deltas and floodplains that were laid down in the age of dinosaurs. Only the tiniest fraction of those great beasts were ever preserved in any part by the process of becoming a fossil; almost all of their elements were returned to the earth, being available, thus, for nature’s processes to recycle them into other forms of life. Given the inconceivable number of atoms and molecules that make up a living being such as ourselves, it is a near-certainty that some of those very same particles that once walked around in a dinosaur millions of years ago are now walking around in us! John Muir said, “When we try to pick out anything by itself, we find it hitched to everything else in the universe.” We do indeed.

It is, after all, a universe. The very term connotes oneness and a wholeness that includes absolutely everything, as in an old verse attributed to Augustus Wright Bamberger, “There’s part of the sun in the apple / There’s part of the moon in the rose / There’s part of the flaming Pleiades / in every leaf that grows.” Ancient peoples sensed this interrelatedness and expressed it with myths and rituals of many kinds. The Roman emperor and Stoic philosopher Marcus Aurelius wrote, “All parts of the universe are interwoven, and the bond is sacred. Nothing is unconnected with some other thing.” He said even more than he knew, because that connection, we now understand, extends even back through all the immense journey of life over several billion years and has links to the farthest reaches of the cosmos.

The nineteenth-century English poet, Frances Thompson, summed it up with the simple and beautiful thought that you cannot pluck a flower without troubling a star. It’s the story told by the fossil that lies on my desk as I write these words.