Problems of Rhaetian stratigraphy with special reference to the lower boundary of the stage

Abstract

The use of ‘Rhaetic’ as an international lithostratigraphical term is rejected in favour of a national terminology. The establishment, type-region and a possible standard section for the Rhaetian, and a marker point for its base are discussed. A critical examination is made of the evidence involved in the suggestion that the Norian and Rhaetian are contemporaneous and that the latter cannot be used as a chronostratigraphical unit. World-wide reinterpretation of faunal and field observations does not support this proposition. Alterations to the lower boundary of the Rhaetian are found to be unnecessary and the suggestion that the Germanic facies should be split from the remainder of the stage and placed in the Jurassic is rejected. The Rhaetian is reaffirmed as the final stage of the Triassic, and the base of the Pre -planorbis Beds supported as the lower boundary of the Jurassic.