Linda Wallace's eyes welled up yesterday as she described the devastation that she and her "human-scenting" dog, Bourbon on the Rocks, encountered during their 13 days searching for survivors of the Mexican earthquakes.

"I was overwhelmed by the size of it, the enormity of it," the Montgomery County resident said after she arrived at National Airport. "The hope was always there that we could find somebody else alive."

Those sentiments were shared by two other area residents, Bill Pierce of Luray, Va., and Marian Hardy of Rockville, who were part of a 17-member search-and-rescue team from the United States that volunteered to help find earthquake victims with 13 dogs specially trained to detect human scent in the air. Hardy founded Dogs-East, a Maryland-based organization involved in training dogs and their handlers for just such special missions.

The three were attending a convention of the National Association for Search and Rescue in Nashville when the federal government issued a request for help on Sept. 13, after the first massive earthquake hit Mexico.

The next morning the trio left in a military cargo plane for Mexico City where, with the help of Wallace's 3-year-old yellow Labrador, they found six people buried alive under collapsed buildings. The rescue effort continued until Friday, when it was canceled because the possibility of finding more survivors had dwindled, Wallace said.

The three dog handlers returned yesterday wearing flag pins that the Mexican government had given them in gratitude and carrying memories of 65 tremors that struck while they were searching the ruins.

Wallace's dog, which went to Mexico named "Bourbon" and came back as "Bourbon on the Rocks" in recognition of hours of rubble-climbing, sniffed out victims as young as infants a few days old, she said.

"She didn't like it when she found a . . . body," Wallace said of her dog. "She'd growl and back away. She wasn't happy."

By the third day of the search, Wallace said, her dog would hide "under the bed because she didn't want to do it anymore."

The teams watched the reactions of the dogs closely "to get an idea if we had a live or a dead find," Wallace said, explaining: "If the dogs thought someone was alive, they'd pick up things, and bark and get very excited."

After pinpointing the possibility of survivors beneath debris, the dog teams moved on and rescue workers began extricating the victims, according to Pierce, who coordinated the dog rescue teams at the American Embassy.

Given the magnitude of destruction, he said, "It was amazing how well it all pulled together."