This was to be the weekend for finding the end of the Endless Caverns. It was John Cloud's bright idea, a combination publicity stunt and celebration of his achievement in bringing the caves back to life after three years of dormancy.

But the end of the Endless Caverns found him first.

Cloud, an ex-traveling man for a big campground corporation, had decided he'd had his fill of breakfast in Washington, dinner in Seattle. He wanted to settle down. When he found the decaying Endless Caverns in New Market, Virginia, he formed an investment company, took out a lease, bought a house in nearby Harrisonburg and set to work putting the tourist attraction back in shape.

He worked eight months, restoring the huge old lodge at the cave mouth, rewiring the lights along the mile-long commercial section of the cave, building camping facilities. This weekend was to be his coming out. He had Explorers Club members and speleologists from New York, Philadelphia, Washington and Norfolk lined up to launch an assault on the cave. It was to be the third attempt to find the end since the caverns opened in 1920.

But last week the money ran out. The Small Business Administration turned down his application for a loan to buy the caverns for half a million dollars, he said. And when the loan collapsed, so did his plans. On the spot, he closed down.

No one will find the end of the Endless Caverns this weekend, because there's a chain at the entrance. It's up for sale again, this time with the ante up to $550,000.

More's the pity, because as cave-owners go, Cloud had the right idea. He had a kind of boundless enthusiasm for his cave, a curiosity that led him to make the trek to the deepest recesses man had ever visited.

He took me there two weeks ago in the dead of night. We were armed with carbide lanterns, hardhats and ropes, and wore the grubbiest clothes we could find. We labored five hours to get to the spot where the Explorers had called it quits 11 years ago, and from which they intended to press on before this weekend's expedition was canceled by finances.

It was a whale of a voyage, including a hair-raising slide down a 90-foot chute to the old stream that carved the tomb-like caves millions of years ago. We crawled through holes no more than 15 inches around, skittered along on hands and knees under rock ledges that didn't end until they peaked atop Massanutten.

We labored that way for hours, and in the end we found a plastic bottle suspended from a stalactite with the information that no man had ever walked farther in the caverns than we. And we, of course, walked a few feet farther to make our mark.

Caves are weird places. Endless Caverns was formed by the workings of water and limestone. The underground stream cut through the stone, then seepage from groundwater alternately built and removed stone in the forms of stalactites, stalagmites, flow stone and other varieties of rocks abuilding.

These processes left huge open "rooms" in some places, great rooms strewn with broken-down rocks in others, tiny crawl-spaces elsewhere. Dotting the pathways are perilous pits -- holes that extend straight down farther than the light from a bright lamp can reach.

"Go down one of those," said Cloud, "and you'll never come out."

The caverns are as dark a place as there is on earth, always clammy, with 100 percent humidity, and always between 50 degree and 55 degree F. Strange bugs and animals live there, including blind shrimp in the stream, bats, spider-like arthropods and one species of beetles that is known to exist nowhere else.

If Endless Caverns never reopens to the public, it will be a significant loss. According to Dr. John Holsinger, a biospeliologist at Old Dominion University who searched for the end in the 1967 expedition, "It's a caver's cave. The kind you can get into, with some excellent formations and some interesting biology."

Endless is the biggest cave in the Shenandoah valley and the 13th largest in the state. It's also the biggest commercial cave in Virginia, with 8,300 feet of mapped trail. Only the first half of that is lighted and open to the public. Was, we should say.

The loss of Endless Caverns puts the number of caverns open to the public within a reasonable drive of Washington at four, according to Holsinger. There's Luray, on U.S. 29; Massanutten, off U.S. 33 east of Harrisonburg; Shenandoah, on U.S. 11 north of New Market and Skyline, off Skyline Drive at Front Royal.