A Walk in the Sun
from the book, "Petrified Lightning"

Petrified Lightning

A Walk in the Sun

During the late 1980s a group of scientists from the University of California, Riverside, unearthed a series of footprints made by ancient Native Americans wandering along the banks of the Mojave River in San Bernardino County, California. These are the oldest known human footprints in North America.

Judging from the size of the prints, these early wanderers comprised two adults, a male and a female, and two young children—just a typical American family out for a walk in the sun. The scientists found a total of 54 prints. The adults were walking in a southerly direction, and the children appear to have been playing, as their tracks go in many directions, although they generally followed their parents. On the soft, rain—soaked ground the tracks left deep impressions as evidence that people had passed by.

A short time, possibly a week, after their passage a grass fire swept the area and baked the clay, thus hardening and preserving the footprints. Charcoal from the burned grass, subjected to radiometric dating, yielded an age of over 5,000 years.

The forces of erosion and weathering usually obliterate signs such as tracks, so a find of this sort is considered quite spectacular. Nevertheless, a fortunate set of circumstances does occasionally occur, and a few of the trillions of tracks left by humans and other animals have been preserved. In Nicaragua a series of slightly older human footprints has been preserved for about 6,000 years since several individuals walked over a soft volcanic mud one day. A volcano had evidently erupted, and a shower of ash covered the area. Rain turned the surface into soft mud, and over this surface the ancient people walked and left their marks. Their flat prints close together suggest that they were in no hurry, and all were walking in the same northerly direction. The hot tropical sun baked and hardened the volcanic mud, retaining marks of the footprints. Another eruption followed and ash buried the prints, thus guaranteeing their preservation.

The study of fossil human footprints has become of primary interest to paleoanthropologists. By determining where, when, and with whom the early humans walked, scholars can make many inferences about lifestyle. The prints found in the cave of Le Tuc d'Audoubert reveal much about the customs and religion of the Cro—Magnon. The cave's large galleries and chambers have remained intact and almost completely unchanged since Paleolithic times. The visitor proceeding down the narrow passage will pass several prehistoric footprints of humans and cave bears. Finally, over 2,000 feet from the entrance, is the place where the famous Bison Sculptures are located. The clay bisons, a male and a female, are each about two feet long. These sculptures are no mere primitive carvings, but are works of surprising plastic beauty, rich with life and filled with an astounding force of expression.

The floors are covered with footprints of the artist. The oversize prints indicate that he must have been a large man, and this is confirmed by the imprints of his broad, heavy fingers on the clay as he molded the bison. The main evidence of paleolithic activities at Le Tuc is documented on the smooth floor of a low—roofed chamber. Some extremely simple abstract finger tracings are etched on the floor, along with 50 deep human heel marks visible in the clay.

The absence of any toe prints suggests that whoever walked across the chamber did so in a most unusual fashion. All of the heel prints are small and narrow, evidence that the room was used by children or adolescents. This is further confirmed by the fact that at no point is the ceiling higher than five feet. The deeply impressed heel marks validate the conjecture that this chamber was used for the ritual initiation of young hunters. The heel marks follow five different paths, indicating the ceremony was directed and controlled as a sort of ritual dance. Further evidence of a puberty rite is borne out by the presence of five sausage—shaped clay forms, obvious phallic symbols. Since the room was well away from the normal route through the caves, its use was apparently restricted to initiation ceremonies practiced so frequently among primitive peoples in the modern as well as the prehistoric world.

Such exceptional remains as artwork and footprints are most likely to survive only in very remote chambers of a cavern, where they are protected against vandalism and casual explorers. Even more important, conditions of temperature and humidity must remain fairly constant regardless of weather changes in the outside world. Le Tuc d'Audoubert is one such preserve; another is the painted cave of Niaux in the central Pyrenees.

In a newly discovered gallery at Niaux are some 500 well—preserved human footprints that seem to be associated with five black animal paintings—a horse, three bison, and what appears to be a weasel— grouped in one part of the gallery. The footprints are of individuals of all ages, and they seem to be performing a ritualistic dance in front of the paintings. The children's prints suggest that they did not take the services very seriously. They seem often to be at play, chasing each other or dabbling in the mud, making impressions of their hands or other childlike images. The painted chamber is at least 2,000 feet from an entrance to the cave, so these remote salons were obviously for ceremonial use and not day—to—day living.

To stand silently in this painted chamber covered with the footprints of antediluvian life is a strange experience. Visitors have said they felt the presence of those ancient hunters so vividly that many succumb to the temptation to look over their shoulder to be sure that no one else is standing in the chamber. Nearly 200 centuries separate the visitor to Niaux from the children who danced and chanted their way around these muddy galleries. Since they left 20,000 years ago, their ancient playground has remained undisturbed until the present, except for one incident.

Three young visitors entered Niaux from an unidentified entrance long after the ice age hunters had passed into oblivion. These later visitors appear to have been three children who carried wooden torches and left small footprints on a sand bank near some of the wall paintings. They must have felt like visitors to the Louvre in Paris as they viewed the ancient art. Burned carbon droppings from their torches permitted scientists to apply radiometric dating to the time of their visit. It was calculated to be about 8000 b.c., over 10,000 years after the Stone Age paintings were executed. Apparently no other human was in this gallery at Niaux until its discovery in 1970.

The Cave of the Witches, near the city of Genoa in northwestern Italy, was so named by the ancient Romans because they believed it was inhabited by witches. Many years before the Romans, however, the Stone Age Neanderthals had lived there and had their own superstitions about the cave.

Evidence of occupation by Neanderthals had long been established, but scientists believed it to be more than a residential site. In 1950 scientists opened a new section of the cave, revealing a large chamber in which beautiful stalactites hung from the ceiling and impressive stalagmites grew from the floor. The entrance to this chamber appeared to have been blocked by a natural landslide. This was not the case, however. Eons ago powerful arms piled huge rocks at the opening, sealing off the interior. With the passage of time the barrier took on the aspects of a rock slide.

As the light from electric torches flooded the newly discovered chamber, the scientists found well—preserved footprints of several adult Neanderthals. Before this, little had been known of the physical appearance of these ancient troglodytes; now the impressions of their feet showed that they walked completely erect in the same manner modern people do. In fact their footprints were identical with those that a human of today might leave on a muddy path. The Neanderthal was truly in the family of Homo.

Nearby was the stump of a torch and, on the wall, a sooty, unmistakable human handprint. Radiometric dating by carbon 14, with an outer limit of 60,000 years, showed that this handprint was too old to date by this method. Scientists believe that the hand and footprints are at least 70,000 years old.

Footprints of humans from farther back in time become, not surprisingly, more and more scarce. To find any prints preserved from earlier cultures becomes increasingly rare, but such finds do happen. Near present—day Demirkoput, Turkey, an ancient hunter paused to rest from his perennial search for food just as a nearby volcano erupted violently, spewing forth fire and ash. The terrified man ran at breakneck speed for the nearby Gediz River. Sprinting over the soft volcanic ash, he left footprints, several of which were preserved. The eruption was probably of short duration, as the ash deposit is not thick. The hot sun baked the volcanic clay that bore impressions of his feet, and they were preserved as solid rock. Recently they were exposed through erosion.

The man must have run in panic, as the prints are almost a yard apart, and the toes were impressed quite deeply. We will never know if he made it to the river, because the prints that survived are over 250,000 years old. He was a specimen of Homo erectus.

The most spectacular story yet to unfold in our prehistory happened eons ago in East Africa at the onset of a rainy season. In that distant time the landscape stretched, much as it does now, into a series of savannas punctuated by wind—sculptured acacia trees. Not far to the east of the site lay the somewhat restless volcano now called Sadiman. It occasionally spewed ash over the flat expanse known now as Laetoli. Laetoli lies on the southern edge of the Serengeti Plain, the site of some of the most spectacular game migrations in the world. Its landscape 3.6 million years ago was surprisingly similar to today's typical East African savanna.

Animal life was quite abundant, and none of the numerous footprints suggest panic. Their wanderings were typically random in their routine quest for food, and they remained unshaken by the frequent eruptions of Sadiman. They had doubtless become accustomed to the rumblings and spewings of the neighborhood volcano. Several times it blanketed the plain with a thin layer of ash. Tentative showers, the precursors of the heavy seasonal rains yet to come, moistened the ash. Each layer hardened and preserved in remarkable detail the footprints left by the ancient fauna, none of which ever seemed to be in a hurry. These ancient deposits containing the footprints are geologically the oldest at Laetoli; they have captured a frozen moment of time from the very remote past—a pageant unique in prehistory.

The gray petrified ash beds hold the footprints of extinct elephants, hyenas, hares, large running birds, and, most important, a series of hominid footprints remarkably similar to those of modern man. The makers, among the ancestors of today's humans, laid these prints down an incredible 3.6 million years ago.

These exciting prints were discovered almost by accident. In 1976, after a hard day's work, two visiting scientists were returning to camp. Serious work was over briefly at the Leakey dig at Laetoli in northern Tanzania. The scientists, lacking play equipment, relaxed by throwing elephant dung at each other. As one scientist ducked to avoid a missile, his face came close to the ground surface of volcanic ash and he recognized a set of fossil footprints. That ended the horseplay and began a serious investigation of the area. By 1978 the prints were established as the greatest anthropological find to date. They were indisputable trackways of three hominids who lived here during the Pliocene epoch.

The volcano Sadiman periodically spewed forth great clouds of steam and ash. This was a particular kind of ash that contained carbonatite, a substance that dries into cement—hard layers when slightly wet. This was crucial in preserving these ancient hominid footprints. The event must have occurred when the dry season was giving way to the wet. As the excavations continued, impressions left by raindrops became common. The laminated ash clearly came from Sadiman in a series of short episodes, each represented by a single discrete layer.

Sadiman's periodic eruptions over about two weeks apparently weren't fierce or intimidating, for the antelope, hare, giraffe, fowl, and other residents of the ancient Laetoli community seemed to go about their business as usual. From time to time the landscape must have resembled a gray beach with scores of footprints impressed in the newly deposited ash. The ash, with its record of prints, was set and preserved into a rock—hard layer of volcanic cement called tuff. This would be followed by another eruption from Sadiman. More ash would fall. Thus these layers of hardened ash built up to a thickness of over six inches.

Late in the first week three hominids walked over the most recent ash fall and left their prints encased in the soft surface. It had rained just before their walk, because rain imprints are on the adjacent ash surface but not on their footprints. The sun was probably shining after the shower had passed. Shortly afterward Sadiman erupted again, and the prints were buried. The process was repeated several times before the rainy season began. By this time the print—bearing volcanic tuff was hardened cement; otherwise all would have washed away.

The footprints the three hominids left in the ashes definitely demonstrate that the earliest human ancestors walked fully upright with a bipedal (two—footed), free—striding gait. The tracks, nearly 60 footprints in all, run from south to north for about 80 feet before ending in an erosional gully. Two of the tracks run side by side. Judging from the size of the prints, the larger individual was a man who stood almost five feet tall. The smaller adult was a woman a little over three feet tall, and a third individual, the smallest, left its prints superimposed on those of the man. These prints seem to be those of a small child playing "follow the leader," just as chimpanzee young are known to do. The man must have walked slightly ahead of the woman. Their prints are so close together that side by side they would have constantly jostled and unbalanced each other.

One cannot help but reflect on this first nuclear family that took a walk in the sun nearly 3.6 million years ago. They could have been the ancestors of the family of Native Americans who walked in the sun along the Mojave River in California just over 5,000 years ago!