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Sunday, February 8, 2009

A mammoth discovery

By Ronald W. Powell


Construction workers discovered the remains of an adult Columbian mammoth this week at the future site of the Thomas Jefferson School of Law. San Diego Natural History Museum employees Pat Sena, (from left) Sarah Siren, Chris Plouffe, Jennifer Nash and Maggie Carrino worked to uncover a skull (center) and tusk (right). Paleontologists from the museum estimate the remains are about 500,000 years old. (Laura Embry / Union-Tribune) -

Former President Thomas Jefferson would have appreciated the discovery yesterday of an 8-foot tusk, skull and foot bones of a mammoth unearthed at the downtown construction site of a law school named for him.

The remains of the adult Columbian mammoth were found in the East Village, where the Thomas Jefferson School of Law is building its new $68 million campus. Paleontologists from the San Diego Natural History Museum estimate they are about 500,000 years old.

While serving as president in the early 1800s, Jefferson had fossilized bones of a mastodon found in Ohio shipped to the White House so he could examine them, said Rudy Hasl, the law school's dean.

“He was just fascinated with these large creatures,” Hasl said. “It's particularly appropriate that there is a connection between this find and Thomas Jefferson.”

Paleontologists from the museum are excavating the bones for transport to the museum for detailed study. They say the bones hold clues about animal life in the downtown area a half-million years ago, as well as indicators of climate changes that varied from hot to cool in eons past.

“It's a pretty important find,” said Pat Sena, a paleontologist for the museum who identified the bones yesterday morning. “The mammoth itself is a pretty rare find, and this is a really intact skull, foot bones and tusk.”

The museum has collected mammoth tusks elsewhere in the county, but this is its first skull, said Thomas A. Deméré, the museum's curator of paleontology.

“This was the largest land animal of its time,” Deméré said.

Construction workers spotted what they believed was a fossilized redwood Tuesday afternoon, several feet below street level at Island Avenue and Park Boulevard. Sena called for work to stop in that corner of the construction zone yesterday morning when he determined that the fossil was the animal's right tusk.

“I saw a piece of tusk fragment and started digging on in,” Sena said.

The mammoth was 20 percent larger than the modern elephant and lived during a dry period in the area, Deméré said. That's apparent because there is a layer of dirt containing the shells of marine creatures below the bones and another shell-rich layer above the mammoth fossils.

The position of the mammoth fossils – in a stratum that also included the bones of rabbits and rodents – indicates that the mammoth roamed the area at a time when the waters had receded.

Sena, who monitors construction sites for the museum, said he has found mammoth bones in Oceanside, Carlsbad, and the Borrego Springs area.

“It shows that the county was teeming with mammoths and that it had a savannah environment,” he said. “It was a lot wetter than it is today.”


Ronald W. Powell: (619) 293-1258; ron.powell@uniontrib.com

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