The Daijima Formation, originally described as non-marine (HUZIOKA, 1959), is uncon- formably overlain at the type locality on the Oga peninsula by the marine Nishikurosawa Formation. However, recent discoveries of marine fossils (OKAMOTO, 1980 MS etc.) indicate that there is a possibility that the Daijima Formation could be marine, at least in the northern half of the area that has been desc- ribed as the Daijima Formation. Both the Daijima and the Nishikurosawa Formations were influenced by a warm current environment. The former is characterized by the Daijima flora (HUZIOKA. UMEMURA, 1979); the latter by warm planktonic foraminifera (IKEBE, 1962).
