If you look up the Blackwells Island Light or Roosevelt Island Lighthouse, you’ll find a version of this story: The lighthouse was built in 1872, with James Renwick Jr, who was perhaps NYC’s most famous architect, supervising.
Until the late 20th century, a stone stood at the base of the lighthouse said, in finely chiseled letters:
THIS IS THE WORK THAT WAS DONE BY ME, JOHN MCCARTHY, WHO BUILT THE LIGHTHOUSE WITH HIS OWN HANDS, FROM THE FOUNDATION TO THE ROOF. ALL WHO READ THIS PRAY FOR THE REPOSE OF HIS SOUL.
Most accounts online say that McCarthy was a patient at the Lunatic Asylum, an Irish stonemason, who built the lighthouse–maybe under Renwick’s direction, maybe not? Renwick designed many other buildings that were owned by the NYC Department of Corrections and Charities on both Blackwell’s Island and nearby Ward’s and Randall’s Islands, so maybe he was considered the supervising architect by default? So maybe he designed it but McCarthy executed the construction?
Then, some accounts claim that McCarthy was the same person as Thomas Maxey, who built a fort around the same location as the lighthouse, and reclaimed the land that the lighthouse was on. And some people seem to suggest that Thomas Maxey didn’t exist, and McCarthy was the one who built the fort?
Basically, a lack of good records have made this lighthouse the subject of tons of speculation and urban legends, which like most urban legends, end up being a photocopy of a photocopy of a photocopy and get distorted.
Oh, also, another weird wrinkle: the stone giving John McCarthy credit for building the lighthouse disappeared during the 1960s, and no one knows what happened to it.
To learn more, check out the episode I did about this Victorian lighthouse, or read my essay The Ghosts of Hell Gate in the Feminine Macabre!