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Fossils Are More Than 1 Million Years Older Than Those at the La Brea Tar Pits

ROSEMEAD, Calif., Sept. 21, 2010 — The most comprehensive collection of fossils of its era in Southern California, more than 1 million years older than those at the well-known La Brea Tar Pits, was discovered by Southern California Edison (SCE) paleontologists.

The historic finding occurred at a site in Riverside County on county-owned land where SCE is building its new El Casco Substation. As part of its work to prepare the land for the substation near San Timoteo Canyon, SCE had staff and contract paleontologists and biologists carefully monitor construction grading at the 28-acre site. Because of the soft sediments in the soil, SCE expected to find some fossils, but nothing close to the size and scope that was discovered.

“This is an incredible find,” said Rick Greenwood, SCE’s director of Corporate Environment, Health and Safety. “These fossils rewrite the history of this area. Because of SCE’s significant discovery, students of science everywhere now will have an exciting new collection to explore allowing them to learn more about this important era.”

Currently, sediment is being removed from the fossils at a lab of LSA Associates, Inc. in Riverside, an SCE contractor. LSA also is cataloguing the fossils and reassembling and reconstructing some of the larger fossils and sorting microfossils.

The fossil collection contains specimens estimated to date back 1.4 million years to a period known as the Irvingtonian North American Land Mammal Age. The collection is about 1.2 million years older than those from the better known Late Pleistocene era, such as fossils at the La Brea Tar Pits.

The El Casco collection is estimated to contain more than 1,450 specimens, including about 250 large vertebrate fossils (bigger than rabbits) and about 1,220 smaller vertebrate fossils (rabbit size and smaller). More than 27 different kinds of fossils have been identified.

Some of the fossils discovered during construction grading last fall are extremely rare. Some are notable for their relative completeness. Among those are a small, saber-toothed cat known as Smilodon Gracilis, which is 1 million years older than its descendant a larger saber-toothed cat, Smilodon Fatalis, at the La Brea Tar Pits.

Among the largest pieces in the collection are two ground sloths, at least two types of camels, a llama, horse, deer and two cats. Plant fossils include birch, pine, sycamore and oak trees.

In the early part of the excavation process last fall, SCE contract paleontologists discovered the fossil of one of the ground sloths, a finding that drew attention in the region and the paleontology community.

The entire collection, known as the El Casco Fauna and Flora, is scheduled to be transferred this fall to Western Science Center in Hemet. The fossils are expected to be on display at the museum sometime next year.

Supervisor Marion Ashley applauded the cooperation between Riverside County and SCE officials that will keep the collection in Riverside County.

“These fossils provide tremendous insight into our past. Hidden for eons, they now offer scientists and our community a permanent collection for research and education,” he said.

The historic discoveries were made at a substation construction site that is part of SCE’s $21.5 billion infrastructure investment project to expand, green and strengthen the region’s power grid. Construction for the El Casco Substation is scheduled to be completed in mid-2011.

 “The El Casco Substation that is being built will provide reliable service to customers in a growing region of Riverside County,” Greenwood said. “It is really important to enhance our system so we can better serve our customers’ needs.”

About Southern California Edison
An Edison International (NYSE:EIX) company, Southern California Edison is one of the nation’s largest electric utilities, serving a population of nearly 14 million via 4.9 million customer accounts in a 50,000-square-mile service area within Central, Coastal and Southern California.


Southern California Edison Discovers Most Comprehensive Collection of Fossils of its Era in Southern California