Deformation Lamellae Parallel to (1013) and (0001) in Quartz of the Coeur d'Alene District, Idaho

The radiocarbon content of contemporary pre-bomb marine shells from the region of upwelling of the Pacific coast of South America has been determined and found to be somewhat similar to the content of shells from the coast of California and the west coast of Mexico. Deviations of up to -8.5 percent with reference to the contemporary biospheric carbon-14 standard have been observed for the Peruvian coast. Values of from -0.35 to -4.04 percent have been obtained for marine shells from the Galopagos group. Problems associated with radiocarbon dates based on shells are discussed.