Students at the Thomas Jefferson School of Law arrived Tuesday for the first day of spring semester classes at a new, $90 million building in downtown San Diego — a facility that revealed a surprise of mammoth proportions during construction.

Construction crews in 2009 discovered the 300,000-year-old remains of a mammoth on the site, and the bones of an even older baleen whale beneath that, said dean Rudy Hasl.

“We found this wonderful connection between paleontology and Thomas Jefferson School of Law,” he said.

Staff from the San Diego Natural History Museum excavated the fossils, and construction chugged along. But the school wanted to incorporate at least a small nod to its predecessors: It included ancient shells from the site into the terrazzo floors, Hasl said.

Thomas Jefferson students will get far more than an interesting natural history lesson from the new facility, however. At 305,000 square feet, the eight-story building has more than three times the space of the old campus, which was spilt into three different buildings.

“This is a building that supports the kind of academic program we’ve tried to foster at the school — one that encompasses interaction between students and faculty, and between fellow students,” Hasl said.

The building includes many indoor and outdoor communal spaces where students and faculty can meet, study and interact. The hallways were designed to be wide and inviting, and the classrooms include state-of-the-art technology. The school has also switched to a cloud computing network, where computer data and programs are more easily shared by users. Hasl said he believes Thomas Jefferson is the first U.S. law school to deploy such a system.

The facility has 12 classrooms, a moot courtroom, two learning centers, two recording studios, a 40,000 square-foot library and future space for both a café and a law clinic. The added space in the new building will allow the school to expand its student body, but it plans to add only 35 J.D. students to the current 990 total, Hasl said.

The school is offering students and staff a free membership to a nearby fitness center, and the library includes a meditation room.

Karen Sloan can be contacted at ksloan@alm.com.