A dusty shantytown on the outskirts of Lima, Peru is the site of an archeological discovery expected to provide new insight into the great Inca civilization felled by the 16th century Spanish conquest. Uncovered from beneath the streets and yards of the little village are thousands of well preserved Inca mummies complete with their possessions and offerings from those who interred them.

The Peruvian, coastal shantytown of Tupac Amaru sprawls eight hectares, a village of unpaved streets and low shacks, crowded by more than 1,200 families. It was founded in 1989 by people fleeing guerilla activity in the Peruvian highlands.

Though Tupac Amaru is not very old, discoveries made beneath its surface are. Peruvian archeologists led by Guillermo Cock dug trenches and found mummies dating back to the 15th and 16th centuries, when the Inca ruled the region. "In some cases," Mr. Cock said, "we had to go all the width of the streets. People were very, very concerned that the houses may fall into the pits."

Before the excavations in 1999, researchers had found only a few dozen mummies in 45 years. But Mr. Cock's expedition uncovered more than 2,200 mummies. They are believed to date from a 75 year span crossing the time of the Spanish conquest in the 1530s. "We started to find amazing discoveries, well preserved individuals," he said. "You can see the skin and their tattoos."

The mummies add up to a scientific sampling of the Inca people. Previous information on Inca culture has come from a scattering of burials. But the thousands of new discoveries represent a wide spectrum of life, from infants to the elderly, the very poor to the very rich.

U.S. anthropologist Johann Reinhard, who recovered the body of a frozen Inca girl in the Peruvian Andes seven years ago, says the new finds offer an unprecedented opportunity to solve some of the mysteries of the culture. Mr. Reinhard said, "They provide us with never-ending sources of insights into the past. The discovery by Dr. Cock and his team of such numerous and well-preserved mummies of all ages and social categories helps tremendously to fill in our knowledge of the Incas."

Many of the burials are mummy bundles, some enfolding as many as seven individuals with their possessions. Some apparently elite Incas still wear the headdress feathers and masks that marked their rank. Delicate shells decorate the graves, accompanied by offerings of gourds, corn, beans, and ceramics.

The dead were not embalmed. Instead, thick wraps of textiles or raw cotton absorbed the body fluids, naturally mummifying them. The arid, sandy soil aided in the preservation.

But by the time the excavation began, tens of thousands of liters of sewage and other liquids dumped in the streets were seeping into the graves, causing the remains to decompose. Bulldozers destroyed other graves in 1998.

The archeologists have worked frantically over the last three years to save what they could, supported by the Peruvian government and the National Geographic Society in Washington.

Already, the discoveries have challenged previous assumptions about Inca life. For example, Mr. Cock said they overturn the notion that Inca culture involved mostly the empire's elite in a strong relationship with local leaders, with little association with the masses. He said, "We thought that the common people were not really into the Inca culture. This cemetery has shown us that that is not completely true. Even the poorest of the individuals show strong Inca cultural elements."

A few kilometers away at Mr. Cock's laboratory in Lima, physical anthropologists from the United States and Canada are examining the remains from the site to answer many questions. Who were the dead? What work did they do? How did they die? How were the people in each bundle were related? Mr. Cock said, "Once we understand kinship, then the objects, the great goods associated with them, the shapes of the bundles are going to acquire a new meaning."

Mr. Cock has no plans to dig again at the site, but said he is frustrated knowing hundreds of subterranean mummy bundles remain.

Shacks cover most of the untapped areas. Schoolchildren play on the dusty field where many of the bundles were found. Their sandals crush tiny bits of Inca corn and human hair that remain on the surface.