Carmel Mission has yielded some of its buried secrets to an archaeological research team exploring the site with a ground-penetrating radar system that detects objects up to 8 feet underground. An underground room is one of them.

"We have found a massive pit located in the room where the Serra memorial crypt is located," said Ruben Mendoza, a CSU-Monterey Bay archaeology professor and principal investigator for the project.

Mendoza and Matt Turner of GeoModel in Leesburg, Va., worked at the mission grounds last week with the probe to map the underground features of the mission buildings and courtyards. Mendoza, who is volunteering for the project this summer, hired Turner using a $12,600 grant provided by the California Missions Foundation.

Mendoza thinks the underground, 20-foot-long pit may be a mission wine cellar constructed 200 to 220 years ago. "My sense is that it could have been elaborate with a cut-stone ceiling, murals and sculpture. It could be the most distinctive architectural feature in the California mission system," Mendoza said.

He speculates that a stone ceiling collapsed into the vault, and the whole area eventually was covered. The radar probe shows the room extends from the adjacent museum exhibit room to underneath the crypt.

Mendoza said the parish, pastor and curator will make decisions about excavating, restoring and opening the wine cellar to the public. If approved, work could start as early as this fall.

Under the floor of the main church, the men could see layers of American Indian remains. When asked how many people are buried there, Mendoza said it was not possible to know, but pictures transmitted to the computer screen clearly showed the layering of burials.

Directly in front of the church altar is a steep drop-off. Oral tradition has related that an underground space used to store vestments and other relics was in that area, but Mendoza said he expected to find the underground room behind the altar, not in front.

In the courtyard in front of the church, Mendoza said, he believes they found the palisade, a wall constructed to protect the compound. It was probably erected in 1771, when Padre Junipero Serra moved to the Carmel Mission from the San Carlos Mission in Monterey.

"There is also something under the library area," Mendoza said, noting it might be an antechamber to the wine cellar.

Mendoza said he was tremendously excited by what the survey was showing. The final data, which Turner will produce within two or three weeks with his computers back in Leesburg, will be much more detailed than what they are seeing now on Turner's laptop computer.

Turner resembled a character from the "Ghostbusters" movie as he gathered the data. With a vestlike carrier for his computer, he walked long, straight lines across the mission courtyards and through the buildings. He watched the results come up on his computer screen as he dragged his high-tech equipment along behind him in a small, plastic box sealed with duct tape.

Use of the technology is relatively new in the field of archaeology, Mendoza noted. "It's expensive, and others say it takes away from the traditional excavation methods. But when you extricate, you destroy. We call this non-invasive archaeology. It permits us to get a great deal of information with a minimum of destruction."

The men were on the lookout for the wine cellar because of information passed along by Harry Downie.

Downie, who began restoring the Carmel Mission in 1931, told the current Diocese of Monterey curator, Sir Richard Menn, that he had uncovered a stairway leading to a cellar constructed with cut stone. Downie found a human skeleton in the room with a musketball lodged in its spine.

Mendoza said he doesn't know if the remains were left in the cellar or reburied elsewhere after Downie found it.

If they excavate and find the skeleton, forensics experts could determine if it is European or American Indian, Mendoza said.

A saber Downie found near the skeleton is on display in the mission museum. Mendoza said military historians have dated the saber to the time of the Col. John C. Fremont military exploration in 1846.

During the spring semester, 30 of Mendoza's archaeology students worked on an excavation in the courtyard outside the crypt room. They found some artifacts but no staircase to the wine cellar.

Peter Caravella, a CSU-Monterey Bay student, is creating a detailed map of the above-ground mission structures using global positioning systems and geographical information systems. The mission grounds were mapped in the 1920s, '30s and '50s, but the maps are not accurate, Mendoza said.

In years during which the Carmel Mission fell into disrepair, many squatters lived on the grounds, Mendoza recalled. They dug holes called barrow pits, possibly looking for treasure left by the missionaries. "Then, when they didn't find anything, they used the holes to store food or dump trash," Mendoza said.

The underground survey should turn up a number of barrow pits for possible excavation. Ceramics and wine bottles from the trash pits can be studied and dated, Mendoza said. "What they saw as trash in their days, we might see as treasure today," he said.