PLYMOUTH — Every American schoolchild knows the story of the Pilgrims’ settlement of Plymouth. But even the most exacting US historian cannot say for sure precisely where that settlement stood.
Now, a team of archeologists is digging through the sand at the bottom of Burial Hill in Plymouth center, their hopes set on unlocking a mystery that has intrigued researchers for generations: the location of the early 17th-century palisades that would define the original borders of the town that calls itself America’s Hometown.
“If we could find the remains of the original settlement it would be a huge find,” said David B. Landon, an archaeologist at the University of Massachusetts Boston who is leading the excavation. “For an archaeologist this would be a dream come true.”
Achieving this dream is a challenging task. The riddle is complicated by the way Plymouth grew out, each generation tearing down and building over and burying the past.
What is known is that the Pilgrims built their first fort atop the hill, with its sweeping view of their houses and the harbor beyond it, and in 1622 enclosed the fort and their settlement with palisades that extended down toward the waterfront. But those walls were later removed. By the end of the 17th century the entire hill had become a cemetery, and today, most of the territory believed to be within the original borders of Plymouth village is either paved over or built over.
The grassy area along School Street, at the bottom of Burial Hill, is owned by the town, but no one had ever dug there, in part for fear of disturbing unmarked graves.
The UMass Boston survey team used ground-penetrating radar — a geophysical survey device that allowed them to avoid graves while identifying foundations of 19th-century structures that once lined School Street. The researchers believe these buildings may be located on the sites of early 17th-century homes.
“Our interest is in the historic structures,” said Landon, who is associate director of the Andrew Fiske Memorial Center for Archaeological Research at UMass Boston. “We are not disturbing any burials.”
The dig is a reminder that Plimouth Plantation, the place visited by school children, tourists, and other visitors over the years, is actually an historical recreation located 3.5 miles from the original settlement, which is in the current Plymouth center.
If the archeologists find the structures that stood while the palisades were there, that could lead to evidence of the walls themselves.
“We’re digging here in part because we think we might be close to where one of these walls came down from Burial Hill,” Landon said.
The findings so far have been modest. The dig as of Thursday had produced bits of pottery and porcelain, metal straps, rusted nails, charcoal, brick, and discarded oyster shells — evidence of the 19-century use of these structures as stables, storage areas, and a place to dump household garbage.
“It would be cool if this layer of sand that we’re just getting into had some 17th-century stuff in it,” said Eric Johnson, who is pursuing a graduate degree in historical archeology at UMass Boston. The older stuff, he said as he scraped the sand at the bottom of a four-foot-deep test trench, would be thicker, coarser: ceramics would be stoneware, the nails handmade.
Finding the 17th-century layer would be only part of the challenge. Any wood left in the ground from the palisades would have rotted away long ago.
“Essentially, you can identify the stains that are left in the soil from the actual posts that were used to construct something like this,” Landon said.
Behind him, red, blue, and yellow flags marked the geophysical survey area along the bottom of the hill. Several workers were using a giant sifter to go through sand dug up from other open ditches where the search for clues has begun.
“The dig is showing us more and more what this area looked like and what we can find potentially,” said Cynthia Snow, of Friends of Burial Hill, a group that seeks to preserve the grave markers in the cemetery. “I think it’s amazing.”
Historians have always known about the palisades -- Edward Winslow, one of the founders of Plymouth County, wrote about them. Various clues have allowed researchers to figure out their rough location, said Karin Goldstein, curator of collections and library at Plimoth Plantation, which is collaborating with the UMass Boston team.
“The coolest thing we could find would be the evidence of the palisades where they ran along the hill,” she said.
The team plans to excavate along the perimeter of Burial Hill, until June 27, but the dig is part of a multi-year site survey and excavation leading up to the 400th anniversary of the Pilgrims’ landing.
If the team fails to make the big find this year, Landon said, they will continue next year. Not that he was giving up.
“Hope springs eternal with each turn of the trowel,” he said.
David Filipov can be reached at David.Filipov@globe.com. Follow him on Twitter @davidfilipov.