If just one more shovel of earth had been removed, the curious figurine of a kneeling woman carved about 900 years ago might have ended up in a 19th century curio shop.

Or lost forever.

Instead, archaeology graduate student Steve Boles found the rare, 6-inch-high artifact this spring at a massive archaeological dig now under way at the old National Stock Yards to make way for construction of a new $670 million Mississippi River bridge. The figurine and the whole excavation have caused great excitement among archaeology professionals and students.

The sheer size of the dig and the discovery of a buried city dating to around 1050 A.D. - the same time that mound and city building also took off at nearby Cahokia Mounds - has raised hope that an old archaeological puzzle may finally be solved: Where did the Mississippians - a non-nomadic, warrior-based agricultural society - come from and why did they build on such a grand scale?

Site manager and archaeologist Jeff Kruchten said that since last fall, 137 dwelling sites have been dug up or are being excavated. Another 500 to 650 are thought to exist, pushing the estimate of the city's peak population to at least 4,000.

Because the site must be fully excavated or be forever lost to construction, the usual practice of digging up only a part of a site to save it for future archaeologists - the strict practice at Cahokia Mounds where only 1 percent of the site has been excavated - has been dropped. Pretty much the whole stockyards site will be dug.

Joe Galloy, director of the survey's American Bottoms Field Station and overall supervisor of the dig, said simply, "This is the biggest look at a Mississippian City ever. It's really a very rare opportunity."

Boles' excavation showed that the figurine had a close call just before the turn of the century when a manure drain pipe being installed at the stockyards was placed just an inch away from where the treasure was found just 3 feet below the surface. Workmen somehow missed finding it.

Archaeologist Brad Koldehoff said that the back of the figurine was charred from a fire that probably destroyed a hut-like Mississippian home and could have produced enough heat to explode the relic - made of flint clay, a soft, reddish substance found in Missouri that dries rock hard.

The roughly carved face of a woman, whose long hair winds down her back, stares impassively. She appears to be holding a conch shell, which were often imported from early people who lived along the Gulf of Mexico.

Like Pompeii, this 1,000-year-old buried city was basically forgotten for centuries. In the 19th century, 45 mounds that surrounded the site were carted off and used to raise certain areas in East St. Louis above flood level.

Galloy said that one important finding is that there was no clear delineation between this Mississippian city and other sites in the area.

"It was like a big urban sprawl. Well-worn trails led everywhere."

Galloy and Kruchten said a key part of learning the answers to the origin of the Mississippians may lie not only with the size and scope of the excavation, but also with the 1050 A.D. date, confirmed by cross-checking radio-carbon and pottery-dating methods. Earlier findings from Cahokia will be compared to what is learned from the stockyards city to determine the significance of the entire Mississippian habitation.

Galloy said he agrees with other archaeologists who believe that Cahokia and its surrounding towns were the beginning of and the cultural center of what became the Southeastern Ceremonial Complex of mound building stretching from Illinois south to Mississippi to Georgia.

"It was the administrative center," Galloy said.

"It's mind blowing," added Kruchten, who spends his days going from "square to square," as each digger's excavation is called.

"We are finding evidence of special buildings that could have been used for religious purposes or communal areas, and of sweat lodges," he said. The evidence of a sweat lodge is a circle of dark stains where a hut's poles once stood with a hearth in the center.

A sweat lodge, widely used among historical American Indians even today, features a small enclosure with an open fire to boil water. The steam and darkness are believed to purify body and mind.

Unlike other Mississippian sites, early, more primitive habitations were not found beneath the stockyards city.

"There was nobody there before them. So, it was kind of an empty piece of the flood plain where Mississippian developers came in and for just a hundred or two hundred years or so cut down trees, leveled things off and built mounds," said Koldehoff, cultural resource coordinator for the Illinois Department of Transportation. He formerly headed the Illinois Transportation Archaeological Research Program, known now as the Illinois State Archaeological Survey.

Koldehoff said the 1050 A.D. date is the "Big Bang" for mound building, and was popularly applied to the study of the culture by archaeologist Tim Pauketat, whose book, Cahokia - Ancient America's Great City on the Mississippi, chronicles this sometimes violent culture where human sacrifices were known to occur.

"It was like this big, happening place and then boom, it ends and it just sits there and then the stockyards come in," Koldehoff said. The stockyards officially opened in 1873.

Excitement has caught on among the diggers, including archaeology graduate student Liz Watts of Indiana University.

Recently, she finished excavating parts of two dwellings that came together at one corner. Each posthole stain found in the soil was meticulously charted on a large graph, as were artifacts and household trash, including a small, serrated Cahokia arrow point (a sharp piece of chert that might have served as a skinning knife), a pile of bird bones and a lump of limestone.

The 24-year-old Watts said she has caught the excitement of the dig and like others hopes the answer to the origin of the Mississippians culture might turn up, or at least part of the answer.

As for digging and sifting dirt in 90-degree heat, she said" "All of it may not be flashy and glamorous. That's why I like this kind of archaeology. To me it's all flashy and glamorous."