NEWPORT — Researchers who last year conducted the first archaeological dig at the Newport Tower in about 60 years are seeking to return this fall to further excavate the historic site in hope of solving the mystery of the stone structure’s origins.

Jan Barstad, president of the Chronognostic Foundation, of Tempe, Ariz., will appear before the City Council to ask permission to resume the dig.

“Our major discovery in 2006 was an approximately 18x20-foot site due east of the tower, a depression rich in debris and artifacts,” she wrote in a letter to the council. “Although two 1 by 1-meter excavation units were dug there, the weather turned bad and we ran out of time before we could explore the full extent of the site, so that we had to say, when finished on Nov. 22, that the excavation was not complete.”

For many years, historians and archaelogists have come from near and far to study Touro Park’s tower, also known as the Old Stone Tower. The extensive research has produced a multitude of theories explaining who built it, when and why. Yet the tower remains an enigma.

Some speculate the tower was a windmill built in Colonial times for Gov. Benedict Arnold. Others give credit to 12th-century Norsemen or other early civilizations and say its structure has astronomical implications suggesting it served as a calendar.

Barstad wants her archaeological team to return on Oct. 9 or 10 and conduct its excavation until mid-November. As before, the principal investigator will be archaeologist Ray Pasquariello, of Gray & Pape, of Providence.

Barstad said the dig last year was educational for area students who visited the site.

“It brought an immediate example of local archaeology to children of all ages, residents and visitors. It also brought into sharper focus the uniqueness of the Newport Tower — truly unique as the only structure of its kind anywhere in the Americas….

“The Chronognostic Foundation and Gray & Pape Inc. hope that our organization will be permitted to finish the work we began in 2006 and perhaps even to present the city of Newport with enough facts about the tower and its history so that we can all say: ‘Mystery solved, case closed.’ ”

The council meets at 6:30 p.m. at City Hall.

rsalit@projo.com