On the oriental province of the Tethyan realm in the Triassic period.

Palaeontological studies on the Triassic Bivalvia well advanced in Japan in last three decades, in The Thai-Malay Peninsula and Singapore in last two decades and in China in last decade.These new results are schematized with those of Himalaya, Indochina, Indonesia and Primoria of the USSR in order to sketch the faunal aspect, because the Bivalvia bears greater importance for provinciality than the ammonoids and conodonts which are, on the contrary, two keen indices for age-determination.Recently Nakazawa (1975) and Yin (1981) have discussed the early Triassic provinciality with reference to Claraia and Eumorphotis.On the basis of Claraia griesbachi concentrica Yabe and C. multistriata intermedia Ichikawa and Yin from the Gua Musang formation on the Kelantan-P'ahang border, however, it is acceptable that Malay was located in the eastern Tethyan province in the Skytian age.Li and Ding (1981) instituted two new Olenekian genera, Periclaraia and Guichiellca respectively in the Pectinidae and Pterinidae, both indicating endemism in the lower Yangtze region.Our knowledge is better advanced on the Middle and Upper Triassic bivalves, particularly Carnian and Norian ones.Their comparison is made with the European ones in the level of genera.As a result many European members are known now to be Eurasiatic ones as follows.