The school is in the process of building its $68 million campus in downtown San Diego and had a paleontologist on hand in anticipation of some find.
"We expected to find fossils at this site," said Tom Demere, the Curator of the Department of Paleontology at the San Diego Natural History Museum, "but we didn't think we'd find a mammoth."
Workers discovered the fossils when a backhoe hit the tusks of the ancient animal which was about 20 feet below street level, according to the school.
The school says that the find is fitting considering the namesake for the college was fascinated with mammoths and mastodons.
Rudy Hasl, the law school's dean told the San Diego Union Tribune that as president in the 1800s, Thomas Jefferson had mastodon fossils shipped from Ohio to the White House so he could examine them.
The school says yesterday's find will likely delay excavation of the 8-story building construction for 2-3 weeks.
