Archaeologists have discovered what they think are remains of a barn or blacksmith workshop in North Bethesda that could date to the days of Josiah Henson, a former slave whose autobiography inspired the novel "Uncle Tom's Cabin."

Looking for evidence of what slave life in Maryland was like, archaeologists with the Maryland-National Capital Park and Planning Commission Montgomery Parks and the PBS program "Time Team America" began exploring the Josiah Henson Special Park on Monday. They found evidence of a buried foundation that may have existed in the late 1700s and early 1800s, when Henson worked on the homestead for landowner Isaac Riley.

The dig could accelerate fact-finding efforts that started in 2006, when Montgomery County bought the historic site from private owners. Since then, it has been open to the public for tours of what was Riley's home, parts of which date to the early 1800s, and of the grounds where Henson worked.

"It's just invaluable," Montgomery Parks archaeologist Heather Bouslog said of the resources provided and the attention they bring to the site. "I don't know how many people are aware that Josiah Henson, who is the model for 'Uncle Tom's Cabin,' he was living right here in Bethesda."

Archaeologists used technology that detects metals and electric conductivity as well as ground-penetrating radar to find evidence of a rectangular foundation. They looked at old maps and an aerial photograph from 1927 to find it. The site is in the backyard of a neighbor of the park site, who gave permission for the dig.

The scientists says the structure could be a blacksmith workshop because that was Riley's trade. Henson worked for the Riley family from 1795 to 1830, and after he fled to Canada via the Underground Railroad, his recollections of life as a slave were published in 1849. Harriet Beecher Stowe is said to have read Henson's work and used it in writing "Uncle Tom's Cabin," which helped drive the abolitionist movement in the 1850s.

The dig will continue Tuesday and Wednesday.

PBS producers say they were intrigued not just by the site's significance in the history of slavery, but its location — the dig site is in a backyard on Old Georgetown Road, a main thoroughfare in Bethesda lined with million-dollar homes.

The producers are working on a four-episode second season of the program, which dedicates an hour each to archaeological digs across the country. The production is funded with a National Science Foundation grant to Oregon Public Broadcasting and involves intensive three-day digs at each site.

The second season has received $2.4 million to date, according to the science foundation.

"Archaeology is typically underfunded and slow-going," said Ed Jahn, one of the show's producers. "We want to give a jump-start to what was here, some good research that had already started."

Other sites the show is studying include one of the first pueblo dwellings in Colorado, a 10,000 year-old site of mass bison hunting in Oklahoma and a Civil War prisoner-of-war camp in Georgia. Its first season aired in 2009; episodes including the Henson site dig will air in the fall of 2013.

sdance@baltsun.com

twitter.com/ssdance