IRONING OUT THE MARY ANN FURNACE, YORK COUNTY, PENNSYLVANIA

In January of 2008, the authors attempted to find the remains of the Mary Ann Furnace within Codorus State Park, southeast of Hanover, York County, Pennsylvania. Reportedly the first charcoal furnace west of the Susquehanna River, it was founded by George Ross and Mark Bird in 1762. The furnace and forge made cannons and shot for the Continental Army in addition to cast iron stoves. The furnace operated until about 1801. Armed with a 1770’s hand-drawn map showing the furnace, road, and creek, we set out to pinpoint the location of the furnace. A field examination revealed several steep hillsides high enough to have facilitated loading the furnace. Further examination revealed on one hilltop, bits of limonite, limestone, charcoal, and broken bricks. Near the base of the hill, slag fragments are abundant. A trace of the tailrace can be seen departing the site. This is thought to be the location of the furnace, though no foundation blocks can be seen at the surface. A magnetic survey using a cesium vapor magnetometer showed a significant compact magnetic anomaly at the base of the hill where we believe the furnace sat. This may be a mass of iron, known as a salamander, that accumulated in the bottom of the furnace. A linear anomaly was also located in the field to the north of the expected furnace site. In a stream cut, a pavement of oxidized iron with charcoal fragments aligns with the magnetic feature. We hypothesize this to be waste iron, failed firings that cannot be reprocessed, which had been dumped along a road as fill. This linear magnetic anomaly is buried under two feet of fine silt and clay. Future archaeological excavations may confirm the location of the furnace and true identity of the linear anomaly.