Tetrameryx irvingtonensis Stirton, ancestor to the Modern Pronghorn Museum of Local History Fremont, California |
Animals living on the forest land 1.3 million years ago were probably much different than the animals we see there today. Sabercats and mammoths, now extinct, may have roamed the land, long before the Costanoans began living in the area, before the "Advocate Tree" took root, and long before the Europeans wrote the first historical account of the redwoods.
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| When and How the Irvington Fossils Were Found
Fossils found in the Irvington District of Fremont, California, only 35 miles northeast of Marcel's Forest, allow us to imagine what the animals that roamed the forest land must have have looked like 1.3 million years ago. Most of the fossil finds were excavated from a quarry in the southern part of Fremont during the 1940s by Wesley Gordon and a group of amateur boy paleontologists trained by Gordon. The fossilized bones unearthed by his group later became the bulk of evidence for the world reknown "Irvington fauna," animals that lived in the region 1.3 million years ago. Newspaper and magazine articles in the mid-1940s publicized the discovery and made the boy paleontologists famous. While Fremont citizens have forgotten about the important excavation site in their suburbs, the fossils themselves are still familiar to scientists since they are considered some of the finest mammal fossil specimens of the Pleistocene. The first fossil-hunter in the area was not the group of boy paleontologists who found the majority of Irvington fossils. Instead, the title goes to Lorenzo Gordon Yates, a dentist, whose premier hobby was fossil hunting. Mr. Yates found the first Irvington fossil in 1867 and in the following years sent many fossils to paleontologists in the eastern colleges for study. Because fossilization requires special conditions, only a fraction of vertebrates that ever lived has been discovered in fossil form. One requirement of fossilization is that animal bones must be quickly buried. Quick burial means that oxygen needed by bone-decaying bacteria is reduced. Also, quick burial means that other animals, such as scavenger birds or mammals, can't shred the decomposing body and separate bones. The fossils of the Irvington fauna might be the result of landslides, quicksand, or other natural phenomena. Above photograph is of a mammoth jawbone found by the boy paleontologists. Photo courtesy of Museum of Local History Fremont, California |
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What Fossils Were Found at Irvington (List from Pleistocene Ecosystem by Wesley D. Gordon)
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What Was the Climate of Marcel's Forest Like During the Pleistocene Epoch?
The land that Marcel's Forest now occupies looked much different 1.3 million years ago. Pollen and fossil evidence indicate that the climate was characterized by a wetter, longer rainy season with an average temperature around 9 degrees Fahrenheit cooler than today. The picture at the right is an artist's rendition of land vegetation during the Pleistocene in present-day Fremont. Paleobotanists tell us that the vegetation for the area now occupied by Marcel's Forest would have been similar, however. Vegetation along the central California coast grew as a mosaic. Redwoods were restricted to small, protected areas, or grew along the coast, while chaparral, grasslands, and dry woodlands would have been present on exposed hillsides similar to the vegetation shown in the picture. Drawing courtesy of Museum of Local History Fremont, California
How Did the Pleistocene Animals Arrive in North America? |
The Pleistocene epoch is known as the Glacial Age. About 1.6 million years ago, the earth cooled enough that sheets of ice formed over the northern portion of North America. These massive ice sheets lowered the ocean by as much as 100 to 160 meters (around 300 to 500 feet) below their current level, exposing land previously covered by water. One exposed piece was the land connecting Asia and North America called Beringia (also called the Bering Strait Land Bridge). Animals, including humans, used this land bridge to populate North America. The bear and reindeer apparently entered North America over this land bridge, as did the mammoths and mastodons. Animals migrated the opposite way, too. The camel was originally a North American native that migrated to Asia over the land bridge. As glaciers melted, the ocean water level rose and the Bering Strait Land Bridge became the Bering Strait, a seaway which once again severed the land connection between the two continents.
Examples of Mammals that Probably Roamed the Land Where Marcel's Forest Now Grows |
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