The hayseed in the ratty cutoffs was tensed at the edge of the quarry cliffs, beset by second thoughts. His name was Brian Tetlow and his very good friend Doug was calling him a wimp. The air rang with summer cries and stripling boasts, and light sparkled hypnotically off the green water below.

"I ain't gonna let this cliff puss me out," swore Brian as he peered over the edge. His voice was determined. But, even at 15, life is complex. Before long it was apparent: his legs had given out.

"I'll go off over here," he announced to his buddy. "It's just as high."

Brian wasted no time capering to another spot, and then launched himself airborne with a wild gang-way howl, plunging feet first into the depths of the Dickerson Quarry.

It was a leap that daredeveils have een making for almost half a century at this abondoned spring-filled quarry tucked in the oak and poplar forests of rural Maryland, 30 miles from the chlorine and claustrophobia of city pools in Washington. And it was another rite of summer in a pageant that has, inevitably, begun anew. Once again, there is a sense of interlude; of worldly cares suspended; of the seemingly unimporltant times that are impossible to forget long after the things we suppose important are forgotten.

Since it was closed in 1930, the quarry with its 90-foot-deep waters and its dark sheer walls, has been a haunt of teen-agers, some coming from Virginia and the District and places many, many miles away. On weekends crowds have swelled to more than 500. Girls pass dreamy afternoons moisturizing their legs, brushing their hair and acting more sophisticated than they are. The boys mouth off, wrestly and strut to the edge of the cliffs to test their nerve. Out in the middle of the quarry, away from the underwater ledges that taper into the murk, the water seems as unfathomable as girls themselves or this life on the brink of manhood.

This is as it was for people who have long since traded the role of child for parent. Tradition at the quarry lives in rituals that are impervious to time. As you draw near, the sound of splashing and laughter drifts through the woods like an unchangeable song handed across generations.

Once, more than 20 years ago, when the subject of the quarry came up, Montgomery County Councilmember B. Houston McCeney said, "I know when I was a boy I had the best time of my life in that quarry."

Yet today, generations can also be told apart by the quarry, for it is hardly a pastoral vision of the old swimming hole. It is blighted with too many of the hallmarks of contemporary disaffection. The rock walls are scrawled with drug-culture graffiti such as "LSD-25" and "Mushrooms." The water is plied by a permanent flotilla of broken Styrofoam coolers. The bluegills rise to cigarette butts and gobs of spit. Twenty beer bottles fly into the drink on any given day, and kids with reefer-red eyes will describe the grisly aftermath of some friend's illcharted dive. And once, members of a motocycle gang weighted a shotgunned body with cinderblocks and tossed it into the quarry.

Still, as Brian Tetlow says, clambering ashore, "This is our place."

By practice yes, but technically the quarry, which was mined for rock that was used for Georgetown curbs and crushed for roadbeds and filtration plants, lies on private property. Anyone who swims in it is trespassing. But there will be a better mousetrap before the invention that teen-proofs the quarry. Not barbed wire. Not stern signs. Not brandished pitchforks or shotgun blasts of rock salt. Not even 250 bushels of cow manure dumped by dairy farmer Harry Ensor at the had of a few trails that lead to the quarry.

"They're like flies on honey," said Ensor, who has leased the land around the quarry from owner William Anderson for the last 15 years. The dairy farmer can't put his cows in the fields around the quarry because swimmers tear down fences and strew the ground with beer bottle glass. Ensor's moods range from vexed to something just short of homicidal. "I've lived here 34 years and they were going into the quarry then. We've got state police, Montgomery police, but the only way I know to stop'em is to shoot 'em."

Police regularly ticket illegally parked cars, and have made mass arrests for trespassing. Despite police, despite the fact that the quarry has claimed 12 lives over the last 20 years, and despite many mothers forbidding their children to frequent the place, the crowds still come, waxing and waning in size as if part of a cycle that follows its own logic independent of police and mothers.

It is easy to find the quarry even if you've never been there. Just before Dickerson, dozens of "no parking" signs mysteriously appear along Rte. 28. Wherever barbed wire is tangled or a "no trespassing" sign posted, there is probably a trail. If it cuts across an open field the route usually is marked by moldering Michelob cartons. Circle around the dung on the newly blazed Manure Bypass. If you get lost in the woods, look for Cheese Doodle wrappers. Running-shoe tracks can guide you too. Cross the Little Monocacy River on a polished log, and prick your ears for foulmouthed exhortations and the report of bellyflops.

"To keep me out it would take a 12-foot fence and a fleet of airplanes and choppers circling overhead dropping smoke bombs," said Rodger Shields, an 18-year-old known at the Quarry Rat. "That, or if they drained it."

He was sitting on a waterside cliff called Beetle Rock, sipping Budweiser with his friends. ZZ Top spun out of a transistor radio. Battery acid has eaten holes in the Auarry Rat's cutoffs. From his vantage, all the cliffs could be seen, some with names, some with numbers that indicated their height in feet above the water: 34, 42, the rope swing and the famed 65-foot leap called Suicide.

"I've been coming here seven years and I come at least once a day," the Quarry Rat said. "You can get away from it all, from your parents, from civilization. Ou might not see people for all winter long but you'll see'em as the quarry."

Across the way, Gary Sartwell, 21, and Chuck Dorr, a veteran at 26, sipped beer with a friend named Carolyn Bernier, whom they'd just met. Carolyn was 15, and her parents used to swim at the quarry.

"That's Pleasure Rock," Carolyn said, pointing toward the prominence where the Quarry Rat's compatriots were clustered.

"Pleasure Rock!" scoffed Gary."That's Beetle Rock,"

"We call it Pleasure Rock," Carolyn said.

A high yodel burst from the woods and with it, the Quarry Rat, sprinting toward the edge of Suicide. He leaped, arched into space and fell for so many seconds it seemed he would never stop falling, until at last he knifed into the water with a great whoosh, rolling up an ever-widening ring of foamy green ripples.

"Pleasure Rock," Gary said reflectively. "That must be a new generation's name."