It began as a faint, fantastic rumor spread by a Peruvian archeology student who told of a pre-Inca kingdom standing virtually intact in a remote valley high in the central Andes. It was said to have temples, tombs, a fortress and an abandoned gold mine. For Monica Barnes, a young American archeologist who heard the rumor in the fall of 1978 while on a dig in Latin America, there was no choice but to investigate. She left within days for the Peruvian village of Pampachiri—280 miles of treacherous mountain passes north of Cuzco—in the Chicha Valley.

At her first glimpse of the valley, Barnes was sure "something unusual was going on—there was a phenomenal amount of agricultural terracing, which meant thousands of people had once lived here. That was the first tip-off." For three weeks she explored the valley by horse, burro and on foot, stunned by the sheer quantity of plainly ancient artifacts. In one set of tombs she found skeletons, mummy bindings and shards of pottery she believed to be more than 1,200 years old; at another she was astonished to find a town full of circular stone walls—ruins whose architecture certified that they were erected before the Inca empire (1425-1534). But by whom? "There was no way to solve the mystery of who lived here until we could begin to excavate," she says. "The real importance of the area dawned on me gradually."

Exploring her "lost" Andean valley became Monica Barnes' obsession. She and a Dutch colleague, Frank Meddens, 24, devoted the next 18 months to raising money for the dig. Their school, the University of London, offered them $5,000. They also had to locate equipment, research the area and its culture and recruit volunteers dedicated or foolhardy enough to brave the extreme climate and inhospitable way of life in the high Andes for five months—with no pay. Finally, with 14 such souls, including Barnes' and Meddens' fiancés, the team set out last May. They had some borrowed tools and a stake of $25,000—a quarter of what the dig should have cost, most of it raised by Meddens' architect father.

Their route could scarcely have been more difficult, but guided this time by more than rumor—notably two centuries-old texts describing the Pampachiri area in ancient Spanish and Quechua, the language of the Incas—they came upon a prize that more than justified their sacrifice. The Chicha Valley sites, stretching over an area of some 70 square miles, were far larger and more diverse than any in recent archeological history. Potentially they are far more important than the legendary lost city of the Incas, Machu Picchu, which was discovered in 1911. Many of the sites, moreover, were traceable to ancestors of the Incas—the Huari (550 to 1100 A.D.) and Chanca (1100 to 1425) cultures, of which very little had been known before. "Almost no Chanca archeology has ever been done," says Dr. James B. Richardson, an expert on Peruvian archeology and chief curator of anthropology at the Carnegie Museum of Natural History. "It's probably the first Chanca site ever to be identified. It's really very significant." University of California Prof. John Rowe, President of the Institute of Andean Studies, agrees. "This project is making an important contribution."

Of the 65 sites discovered so far, some 10 appear to be Chanca, identifiable not only by the round stone houses (Huaris and Incas built square or rectangular structures) but also by the pottery and stratigraphy—what the diggers find above and below the artifacts. "We've got pure sites of the Chanca period in the exact places where the chronicles say they are," says Barnes. "I'm not talking about vaguely—I'm talking about exactly. We feel we're finding out where these people lived, how they lived, what their houses were like and what social structure they used. And we feel we're helping to explain the Huari culture as well."

The price of discovery has been high, however—and Barnes' story is an object lesson in the perils of a career in archeology. The only child of a steel-worker in McKeesport, Pa., Barnes, 30, admits, "It's a bit odd that I'm in this field, because archeologists usually come from inherited wealth. It's a maxim in this field that there's no future in the past." After Vassar (on scholarship), she married a Harvard physicist and then left him after nine months when he objected to her career. She went on to earn a master's degree at the University of London in 1975. There for the past five years she has been working on her doctoral dissertation and supporting herself on the $4,000 she makes teaching adult-education classes. "I'm below poverty level," she says. "I walk almost everywhere, eat semivegetarian food, don't buy clothes and share two rooms with another woman to keep my rent at $70 a month. By the time I was 18, I knew the profession had too many sacrifices to lead a normal life. But after my first dig, I was inspired."

Apart from expenses, her work on the Pampachiri project has been unpaid—and more grueling by far than any of her previous six digs. Indeed, what kept other archeologists away, she believes, is that the area is "4,000 feet above many people's migraine level." Pampachiri is at 12,000 feet; some of the sites are higher. The altitude afflicted the team not only with migraines but with vomiting and fever as well. Communication with the 500 inhabitants of Pampachiri was impossible for all but the three crew members who spoke Quechua (the official interpreter left in exhaustion after eight weeks). The only place for anyone to sleep was on the stone floor of the marketplace. Bedrolls did little to protect the researchers from the subfreezing temperatures at night; during the day they baked in 100-plus degree heat. The closest outpost of civilization was a seven-hour drive away, and their truck was rarely in working order. They often had to walk to sites several miles from Pampachiri carrying equipment on their backs. Their diet contributed to regular outbreaks of a particularly virulent diarrhea they called "the Inca two-step." The staple meat was guinea pig, and Barnes still hasn't recovered from eating a cat one night. "I lost 20 pounds in three months," she says. "I'm thinking of starting a fat farm in Peru to fund the rest of the dig."

They were sustained by exciting discoveries almost daily. The team's British engineer and its Dutch physician (as the only paid member, he received $800 for the five months) made friends in Pampachiri with their special skills. In return, the villagers helped pinpoint sites of the ruins, many of which were still known to them by the names they were given centuries ago. The team was also guided by the account of one irate 16th-century Inca named Guaman Poma. Living near Pampachiri, he compiled, in a 1,500-page letter to King Philip III of Spain, an indictment of the Spaniards' treatment of the Incas. Poma's letter probably never reached the king. But it was rediscovered in Copenhagen's Royal Library in 1908 and Barnes found it invaluable. "He's got many detailed descriptions of where the towns were, at exactly what bend in the river, where the bridges were, who lived in the towns and what their personalities were like," she says. "In archeological deposits this region is endless. We've already recovered maybe 20,000 pieces, and there are still dozens of undisturbed tombs we're afraid to touch until we're better equipped."

What they have discovered already promises to rewrite Peruvian history. So far the findings may seem small and cautious to the layman. They believe, for example, that the Huari and Chanca cultures made great use of agricultural terracing, a technique previously thought to have originated with the Incas. The team also found physical evidence to substantiate certain theories about pre-Inca culture: that the Indians were coca-chewers (inferred from coca deposits on jawbones), that their society centered on the nuclear family (from the way houses were clustered) and that they were music-lovers (from ceramic lutes, drums and rattles). Most precious among the artifacts are examples of highly ornate Chanca and Huari textiles, which survived in the cold, dry tombs near Pampachiri. Though they would never put it in so many words, Barnes and her teammates believe they are baring the roots of Inca civilization, showing that it incorporated and refined more than it introduced into the history of Peru. "The Inca culture didn't just emerge one Tuesday morning," Barnes' fiancé, David Fleming, explains. "It was the result of long development and absorption of ideas from other cultures."

Fleming, a 28-year-old Rhodes Scholar from Bermuda, jokes with Monica that they'll marry at Oxford next April only if the Chicha Valley project allows them time. As he marked new sites on their map of the valley one afternoon last month he tried to articulate the challenge: "It's part jigsaw puzzle and part mystery. We don't have all the pieces, and we don't know who did it, but this area is stuffed with clues and we're finding new ones every day."

Two weeks ago he and Barnes and the rest of the team left Pampachiri, driven out by the rainy season and the end of their funds. Next spring, assuming they raise the necessary money, Barnes and Fleming will be back. Meddens and his new bride, Beverley, for whom this trip was a rustic honeymoon, have promised to return. So have some of the others. Maybe they will be paid this time, but probably not. What motivates them? "We are discovering new things," says Fleming simply. "It's an archeological cliché to say you're breaking new ground, but we really are."