Five years after the first publication of age measurements by the radiocarbon method (Arnold and Libby 1951) the method has been established as a powerful technique in the study of archaeology. Lists of radiocarbon dates have been published by a number of laboratories (Libby 1951, 1952, 1954, 1955; Kulp 1951, 1952; Broecker and Kulp 1956; Suess 1954; Ruben and Suess 1955; Blau, Deevey, and Gross 1953; Preston, Person, and Deevey 1955; Ralph 1955; Anderson, Levi, and Tauber 1953). A few scientists feel that the radiocarbon dates contradict archaeological or geological theories which they regard as wellfounded and have suggested that because of this the method is invalid.