A Pleistocene Ecosystem
by Wesley Gordon
page 1


Chapter 1. Introduction

After a morning of digging at Locality V3604, three members of a fossil-hunting party the director and two boys sat above the others on a shelf of sand that had been formed by a bulldozer. They rested their backs against a wall of fine sand, which also was formed by extensive quarrying operations. As he finished a sandwich, the director turned his head to the left. Scanning the wall behind him, he spotted the broken ends of two bones protruding from the bank about 3 feet away. The “Fossil!” cry rang out, and everyone gathered around the discovery.

Boy Paleontologists in 1949 look for fossils at the Bell Quarry.

“Before we dig out whatever this is,” said the director, “what else of interest do you see here?” Several boys immediately saw the initials “WH” scratched in the sand about 5 inches above the protruding bines and pointed them out to the others.

“I’m glad whoever put his initials here didn’t have very good eyes,” said one of the boys. “How could anybody miss these bones? He was within inches of them,” added another boy. In years thereafter the group talked about how lucky they were that the unknown “WH” had overlooked the fossil bones.

The sand surrounding the fossil was so fine that the director could remove it with a stiff whisk broom. The bones were about 5 inches apart and seemed slightly curved. After a few moments of work with the brush, the boys were almost certain that the bones were the two big, stabbing teeth of a saber cat. This possibility created much excitement, because remains of this big carnivore had never been found a locality V3604. But as more sand was brushed away, it became apparent that the cat hypothesis would have to be given up. In the first place, there was no enamel on the bones, and, second, the bones were round. The boys knew that the stabbing teeth of saber cats were almond-shaped.

“Well, what can it be?” asked the student.

Phil Gordon in 1950 looking for fossils west side of West Hill looking northeast.

“I know I’ve never seen anything like it,” added the director. “I’m going to concentrate on one bone and find out how far into the bank it goes.” In a few minutes another long had been revealed. Then the smooth, slightly curved top of a skull was exposed, with the two bones attached to it.

“That’s some kind of deer or maybe elk!” exclaimed one of the groups. “Then there must be two antlers on the other side.”

“Those certainly are horns,” agreed the director. “Let’s find out about the other side.” Indeed, two more horns were attached to the other side of the skull. One observer remarked that the fossil looked like “one of those African antelopes.”

“I hope there are some teeth!” someone exclaimed. Unfortunately, there were none.

When the specimen was finally disengaged from the sand, it was gently placed in a cardboard box on top of many pieces of newspaper for safe transport in an automobile. Each member of the Boy Paleontologists was convinced that another new mammal (new to them, at least) had been taken from the Irvington sediments.

Living things are affected by natural forces. Freezing kills certain kinds of seeds but makes possible the germination of other kinds; still others germinate after being touched by the flames of a forest fire. Some fish die in salt water, and some die in fresh water; but some can survive in either salt or fresh water. Seaweeds are absent from water to deep from sunlight to penetrate. The north sides of canyons, hills, and mountains are often hostile environments for plant species that thrive on the south sides, and vice versa. In desert region, not only kinds but also numbers of plants are strictly controlled by the amount of available water. Drought has caused mass migrations of animals, including man; where there is no water, there are no plants and thus no animals. In some arid region, ants must dig as far as 50 feet into the ground to reach moisture necessary for life.

Living things also are affected by each other. A horde of locusts can strip an area of all vegetation in a few hours. Other creatures dependent on the plants must then move out of the area to “greener pastures” or perish. Many of these cannot move far enough to avoid starvation. When muskrat houses become overcrowded, immature muskrats are forced to leave, some almost certainly to become the victims of predators, especially minks. Men have killed coyotes to prevent losses of sheep and young cattle only to discover that after the natural control factor (the coyote) was gone, rabbits and rodents increased in such vast numbers that they caused greater financial loss than the coyotes.

Shortly after man introduced rabbits into Australia, their numbers increased tremendously no Australian carnivores were present to check the increase. Later, since he could not control the rabbits, man bought in weasels to do the job. These energetic carnivores failed to make a dent in the rabbit population, but they are bringing native flightless birds to the brink of extinction.

Such clear-cut evidence of the affects of nature on organisms and of organisms on each other is obviously of great interest to ecologists, scientist who study interrelationships between organisms and their environment. Equally interested are the paleoecologists, who dare to speculate on living things are their relationships with one another and with their surroundings in past geologic times. A paleoecologist bases his speculations on the fossilized remains of organism, on his knowledge of the reactions of modern organisms to one another and to their environment, and on his belief that relationships between living and non-living things in the past were essentially the same as they are today.

Fossils are more than mere relics of the past. They represent active individuals that existed in a world of other living creatures affecting and being affected by them. They represent life, though that life may have existed hundreds or thousands or millions of years ago.

The subject of this book is life that existed during mid-Pleistocene time (about 1.3 million years ago) in central California. Scenes depicting events that might have occurred in that ecosystem will be reconstructed, and, as you proceed, you will make some speculations of your own. Your reconstructed scenes will be based on descriptions of fossilized remains of many animals and few a plants, sediments containing the fossils, your knowledge of the present day world, and your imagination. With the information provided, you should be able to reconstruct the scenes with a reasonable degree of accuracy.


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