 Proponents of the Bimini Road being a manmade feature argue that these radiocarbon dates are invalid because they were obtained entirely from whole-rock samples and subject to contamination from younger carbon.The background data reported by Calvert and others concerning the radiocarbon dates from the Bimini Road demonstrate that not all of these dates come entirely from whole-rock samples.That the dates from the shells and the clearly younger cement holding them together as beachrock are temporally consistent argues against any signification alteration of their radiocarbon content.