The City of Boston Archaeology Program has compiled a history of the 25-foot-deep 19th-century well that suddenly opened up last month in Dorchester's Ronan Park: It provided water for the Pierce family, whose estate sat on the land that was later turned into the park.
The granite slabs and the cobblestone shaft under the fill is almost definitely indicative of a well. Other alternative identifications include a cistern (underground water collection basin) and privy (outhouse), but neither are likely. Cisterns tend to be larger and better lined in order to retain water. They also usually have drains that lead into them from elsewhere. No drains were observed in the shaft.
Privies are usually better lined and are typically, in Boston, rectangular or square. They also tend to be filled in and are not often 2 meters deep from top to bottom- typically they are 6 feet (1.8) deep.
OK, that's the technical analysis.
City Archaeologist Joseph Bagley and volunteer Amy Ohman also compiled the more human side of the story, which began in 1818, when bricklayer John Pierce "purchased 10 acres on the southeast slope of Mt. Ida along Adams Street and built a large brick home for he and his wife, Catherine B. Pierce and their family," before building a second house, next to where the whole appeared. The family story proceeded through the decades to include the saga of a seafaring Pierce who also navigated the Amazon, mysterious intrigues - why did one listed owner and her two children wind up in a boarding house near Fields Corner even as other members of the family became prosperous? - before ending in 1912, when the city bought the property and a neighboring estate to create Ronan Park.
The report also details how the team surveyed the hole, using "an extendable paint roller, an extendable paint roller handle, multiple small battery-powered LED flashlights, an iPhone with protective case, rope, and tape," which let explorers lower the camera down and video the descent.
The report notes that beyond an old metal pipe - an apparent electrical conduit - and parts of the well itself, only one artifact was found, a liquor bottle. But the bottle was plastic, so the report concludes it was likely tossed or tumbled down the hole sometime after it opened up last month.