Steve Butz had heard the local lore about "Indian Ovens" for years, but it wasn't until this past winter that he hiked to a ridge near the Vermont state line to examine the unusual geologic formation stained black by soot from fires of uncertain origin and purpose.
That trek eventually led to confirmation that Native Americans indeed used the site as its name suggests, but it left unsolved another mystery: For what did they use the six soccer ball-sized holes? "The big question is: Were they ovens? Was it a ceremonial thing?" Butz said in a phone interview with The Associated Press.
Butz first heard about the site when he began working for Cambridge Central Schools as an earth science teacher more than a decade ago. The site, atop a 1,500-foot ridge in the neighboring town of Jackson, 35 miles northeast of Albany, had long been known to locals as Indian Ovens. According to local lore, the soot-covered depressions in a vertical rock face were used as cooking vessels by Indians.
Boy Scouts often hiked to the spot and built fires in the holes, so it wasn't known if the soot was from their visits or from use by Indians hundreds or even thousands of years ago, Butz said.
He finally visited Indian Ovens in March after getting permission from the 84-year-old woman who owns the site at the northern end of the Taconic Mountains, a range running along the New York-New England border from northwest Connecticut to southern Vermont. He was accompanied by Ken Facin, a fellow educator and geologist.
Butz said the six "ovens" formed naturally as a result of spherical deposits of quartz eroding out of the phyllite rock face. Three of the holes show evidence of burning. Not wanting to damage the holes themselves, they used a chisel to chip away rock samples from a chimney-like tunnel that connects two of the depressions. Each of the samples had carbon staining from fires.
Butz contacted scientists at a laboratory in Miami that specializes in radiocarbon dating who suggested he first conduct a simple test to determine if the soot stains occurred from more recent fires.
Working with his students, Butz twice soaked the samples in a weak solution of hydrochloric acid to remove any contemporary soot stains. The stains left behind indicated the fires that produced the soot likely occurred a long time ago.
Butz said the Miami lab's radiocarbon tests recently revealed the fires that caused the soot stains occurred between A.D. 1410 and 1450, about two centuries before Europeans began arriving in the area.