There are, by his own description, two sides to Gerald E. Downs II. There's this quiet guy who likes to come home, drink a six-pack and be left alone. And then there's the professional promoter, the Caveman.

Or, as he puts it, "The act turns on, I become a different person."

His stage is the Crystal Grottoes Caverns, the only commercially operated cave in Maryland. Owned by his family for three generations, it was discovered by a blasting crew in 1920 and opened to visitors in 1922.

Downs, 29, lived in Alexandria as a child and spent his summers here visiting his grandfather, Joseph Ralph Downs. The grandson, who worked as a carpenter, electrician and plumber before he took over the family business, says that through his efforts the number of visitors has increased by 20 percent each year since 1981. Last year, there were 50,000, he said.

During the winter off-season, Downs delivers his brochures to any place within 300 miles that will take them, and he lobbies legislators for laws he thinks will help Washington County tourism in general and Downs in particular.

"A lot of people seem to remember us better than the cave," said his wife Peggy. "I think the best businesses are still the family-owned ones."

Downs is the P.T. Barnum of stalagmites, which point up, and stalactites, which point down. But the special effects along the Crystal Grottoes' 900 feet of corridor -- the small portion of the caverns that is illuminated and accessible to visitors -- are all natural.

There are 148 caves in Maryland, about a quarter of them in Washington County. Most are inaccessible; none save Crystal Grottoes is commercialized. The commercial caves in Virginia, including the Skyline, Shenandoah and Luray caverns, are generally bigger operations.

Skyline, for instance, has a miniature train and multicolored lights in its caverns. Luray has its Historic Car and Carriage Cavern. Shenandoah has antiques and coffee shops. By contrast, Crystal Grottoes is modest.

Downs has kept his interior decoration to a minimum.

"Ultimately, Mother Nature is the finest and most exquisite act," he said of the cavern's strange and wondrous shapes.

"When you let the lights on in the Crystal Palace, the curtain goes up, the show goes on," said Downs. "There's this look of wonder on people's faces. All of a sudden, it doesn't become work."

Investing the formations with familiar names, Downs introduces them as the Cave King, the Egyptian Mummy, the U.S. Capitol, Old Father Time and Old Sam the turtle. There are soda straws and spears, blankets and a "worm's eye" vegetable garden, the Frozen Waterfall and a reflecting pool, Golden Lake.

For children especially, the cave is an adventure, "like going out to sea or into space," Downs said.

"Is it scary down there?" asked Erica Jones, 13, who was touring with classmates from St. Paul's school in Baltimore. Downs assured her it wasn't. "I'm afraid of the dark," she said.

There are no bats in this 250-million-year-old cave, just groundwater dripping to create the limestone formations.

"How'd they build the cave?" asked Jim Gillis, 4, a younger brother of one of the St. Paul's students.

"They didn't build it. Water did that," his mother said.

"Okay, folks, we're gonna feel like sardines for just a minute," Downs said as he led the group down a narrow path. Nobody seemed to mind.

"They fought the Civil War right over the top of this thing and didn't know it was here," Downs said, referring to the Battle of Antietam in 1862.

After the tour, the students trooped to the grottoes' small gift shop, which sells the usual tourist trinkets: spoons, toy soldiers, T-shirts, bumper stickers, mugs and glasses, Maryland, Rebel and Yankee flags and plastic Frisbees advertising the caverns.

Upstairs in his office, where Downs and his wife lived for five years before moving into a restored tollhouse nearby, the Caveman keeps scrapbooks. They document his successful struggle for legislation in the Maryland General Assembly to allow commercial "logo" signs on the interstates, where large billboards are banned, and for the construction of South Mountain visitor centers on I-70.

Since the caverns aren't next to the interstate, his logo is not among those displayed there, but the visitor centers carry his brochures.

"He's a real bull terrier," said State Sen. Victor Cushwa (D-Washington County) of Downs. "He bulldogged the local delegation and other legislators about those logo signs. It even got embarrassing. If the governor came to Washington County for any reason, Gerry would be there tugging at his sleeve."

Downs also sought a law making the Crystal Grottoes Maryland's official cave, ranking it right up there in the Free State hall of fame with jousting as the state sport and the Baltimore oriole as the state bird. It failed.

"The cave bill, to be truthful, was a diversionary tactic," Downs said. "We wanted to wake people up in the state as to where we were. Trust me, friend, we didn't lose anything with that bill . . . .

"I used to resent my nickname, 'Caveman,' but I'm proud of it these days," he said. To let people know about his caverns, Downs also occasionally dons a caveman suit for publicity purposes at local parades and carnivals.

Downs takes his cue from his grandfather, whom he describes as "a super salesman."

"When those lights went on, that man was on stage. If my grandfather were alive today, I think that man would have a smile on his face."