The age of the Calaveras skull: dating the 'Piltdown Man' of the New World

The Calaveras skull, first reported in 1866, represents the earliest purported fossil human discovery in California and one of the earliest in the New World. The specimen is in the possession of the Peabody Museum, Harvard University. The validity of the original "Tertiary" age assignment was rejected by the first generation of professional American archaeologists early in the twentieth century. Radiocarbon analyses using both conventional decay counting and accelerator mass spectrometry indicate a late Holocene age for the Calaveras skull.