San Diego Natural History Museum--Your Nature Connection[BRCC San Diego Natural History Museum: Paleontology]


Imperial Formation
Palm Spring Formation
The Ethics of Fossil Collecting

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Paleontology and Our Local Desert

Palm Spring Formation

In the badlands region of Anza Borrego Desert State Park are exposed an approximately two mile thick sequence of sedimentary rock layers, called by geologists the Palm Spring Formation. These sedimentary rocks are thought to have been deposited in ancient piedmont, flood plain, and playa lake settings. Today they are high and dry and steeply tilted to the south. The Palm Spring Formation ranges in age from about 0.9 to 4.0 million years and contains a diverse assortment of fossil vertebrate remains.

The late George Miller of the Imperial Valley College and more recently George Jefferson and his crew of dedicated volunteers at the Anza Borrego Desert State Park have collected fossils in the badlands for many years and have documented a community of organisms quite different from that inhabiting the region today. Using these fossils as a guide we can travel back in time and view this ancient world.

Imagine lions, sabercats, and bears; herds of llamas, long-legged camels, horses and American zebras; family groups of mammoths; giant, solitary ground sloths; flocks of ice age vultures; innumerable small mammals including shrews, gophers, mice, kangaroo rats, and rabbits; and a variety of snakes and lizards. The vertebrate fossils from the Palm Spring Formation provide us with one of the most complete records in the southwestern United States of land life during the transition period leading into the Ice Age or Pleistocene Epoch.

From this brief discussion I hope that the reader can see that to experience earth history we don't have to travel to distant or exotic places like the Galapagos Islands. Instead, we can get the essence of this geologic experience right here in San Diego County, especially in our local desert.

Consider the ethics of fossil collecting.

Thomas A. Deméré, Ph.D.
Curator, Department of Paleontology