Three models for Tethys are discussed. Based on recent data from China and adjacent areas, it is concluded that an archipelagic ocean model for Tethys accords with paleomagnetic and biogeographic data that Eurasia and Gondwana were widely apart, and also accords with sedimentary data that deep ocean deposits were few, because the vast distance were filled by islands.

The base of bed 27c in the Meishan section Changxing County, Zhejiang Province, China, is recommended as GSSP for the basal boundary of the Triassic System. The Meishan section is easily accessible, well exposed, and records continuous marine sedimentation from the Changxingian(latest Permian) into the Early Triassic. The global boundary stratotype point is placed at the first occurrence of the conodont species Hindeodus parvus in the evolutionary lineage latidentatus-parvus-turgida-isarcica, which is transitional between Hindeodus and Isarcicella. Integrated stratigraphic study of the Meishan section includes radiometric dating, and chemo, sequence, eco, and event-stratigraphy. The latter involves the records of possible impact events as well as volcanic, anoxic, and transgressive events. The latter three studies have identified events the appear to be recorded on a pan-Tethyan or even a global scale.