Clearly visible in the marine stone floor of Sonoma State's newly renovated science building are the fossils of ammonites and belemnites, early relatives of the octopus and squid.

"We're glad they chose that; it's a coup for the Geology Department to have a story out in the entryway," geology professor Matt James said.

The $29.5 million, 18-month renovation of Darwin Hall, the university's second-oldest building, has just been completed and the building will be ready for fall classes.

The work brings the building up to modern standards, and is designed to teach some aspects of science that didn't exist in 1967, when Darwin Hall was built, said Saeid Rahimi, dean of the School of Science and Technology.

"It is clearly a night-and-day difference," Rahimi said. Science in 1967 "was vastly different from what we have today."

Darwin will be home to the Biology, Chemistry, Computer Science, Geology, Mathematics and Physics and Astronomy departments. It will serve about 2,500 students, including 1,300 science majors.

Classes will be taught in "smart" classrooms equipped with the latest audio and visual equipment, and in laboratories with more space and better-ventilated work areas.

High-speed Internet access is available throughout the building through a wireless network and computer jacks, and there will be hundreds of computers spread through computer science classrooms and science laboratories.

"Our business is science and science, unlike many other fields, requires facilities, laboratories and equipment," Rahimi said.

The renovation of Darwin, a concrete-walled structure that was gutted, leaving only the stairways and elevator, was designed by SSU architect Christopher Dinno, senior director of capital planning, design and construction.

"It is a specialized building," Dinno said. "It is a totally different use of teaching, and the technology is part of that."

Some of the renovation was for safety. For example, the ventilation shafts from laboratories, where noxious chemicals are often used, were uncomfortably close to rooftop air intake ducts.

The concrete exterior received a coat of paint and an outside portal was enclosed for a lobby.

Inside, the science tone is set by the lobby floor, where the recognizable fossils of marine life can be seen in the thin slices of marine stone.

Ceilings in the basement and on the second and third floors are open, leaving ducts and pipes exposed, which cut costs and added to the science building feel, Dinno said.

The building is constructed so faculty offices are clustered, and sunlight shines through the windows from faculty offices on one side of the building to the laboratories on the other.

The basement and the first floor are set up for general education science courses that are expected to generate the most foot traffic. The larger, airy laboratories are on the second and third floors, along with cages for mice, rats and rabbits and a lab room that can handle three cadavers.

The university is moving equipment into the building even as it goes through the process of accepting it from the contractor. The faculty is expected to move in next month.

The cost is $26 million for the renovation and $3.5 million for furniture and equipment. It was financed with state bonds.