It was during the fifth and last great era in the earth’s history that mammals developed and that man made his appearance on earth. In many places in the world the remains of animals that lived during various parts of this age have been preserved. In the famous asphalt pits of California literally hundreds of the bones of large mammals—tigers, mastodons, wolves and many others—have been brought to light. In the receding ice of northern Siberia, large mammoths—elephant-like animals representative of the last era, but unknown today—have come to the surface with even their skin and flesh preserved. But in the Grand Canyon region few fossils of the more recent times remain to tell the story of the life that then roamed over this surface. For long ages this region has been above the level of the sea, erosion has been continuous, so sediments have not accumulated and consequently few records of life have been made.
Recently near the western Navajo Indian agency at Tuba City, Arizona, however, the remains of several extinct animals were discovered. In a spring, hidden in a sandstone crevice, were found the tusks of a mammoth and some teeth which belonged to camels and bison. These were creatures native to this country not far back in history. They give but a very fragmentary insight into the more recent geologic history of the region, but they open up a field for interesting speculation to the imaginative person.
ELEPHANT AND CAMEL REMAINS
ADVENT OF MAN IN THE SOUTHWEST
(PLEISTOCENE HISTORIC)
After reviewing the chapters of the earth’s history and witnessing the procession and the slow but steady development of life through the ages, it is very natural that one should wonder when man came upon the scene. Compared with the hundreds of millions of years which have elapsed since the time of the first plants, or the millions of years following the first appearance of vertebrate animals, the age of man is as nothing. In the Old World there is evidence that humans existed before the last great Ice Ages, more than a million years ago, but in the Americas human occupation is measured in terms of thousands of years only.
Numerous recent discoveries in widely scattered parts of the Southwest indicate that man first occupied this region at a time when it was still inhabited by such animals as the ground sloth, the mammoth and the camel. Artifacts of stone and bone have been found associated with the remains of these animals. Early man’s camp sites are located along the margins of former extensive water bodies that existed throughout this region at a time when the climate was far more humid than now. Little is known about the nature or habits of these men, but it is supposed that they were hunters with no knowledge of agriculture.
In the Grand Canyon region, the earliest human history with a clear, detailed record goes back only to about 300 A. D. From that time up to the present, however, the story of a flourishing and rapidly changing civilization is well recorded. Although no written documents have been left, abundant reliable information is available as a result of archeological excavations. Even the dates of many important events have been accurately determined through an ingenious method of calculating years on the basis of growth rings in the trees used for house construction.
ANCIENT INDIAN PETROGLYPHS, HEAD OF BRIGHT ANGEL TRAIL, GRAND CANYON