Jed Levin, an archaeologist with the National Park Service, said the pipe bowl is probably not connected directly with the President's House but is relevant to the project's exploration "of the racial and racist legacy that allowed human bondage" at the birth of the nation, The Philadelphia Inquirer said Friday.

Levin said "Negro-head pipes" were quite popular in the middle of the 19th century.

The President's House, which was demolished in 1832, was occupied by George Washington, his family and at least nine slaves during the 1790s. John Adams, Washington's successor, also lived in the house. Adams was staunchly anti-slavery, the newspaper said.