Most tephrochronological studies based upon absolute ages are derived from historical records of eruption and radiocarbon dates from Holocene and Pleistocene times. However, unless associated with some organic matters whose ages are younger than 35, 000 years old, tephra layers usually could not be dated.Recently Kigoshi explored the possibility that Ionium dating could be applied to igneous rocks whose ages are not so older as compared with the half-life of Ionium. The method is expected, when the informations would be increased, to elaborate the chronology of the later part of the Pleistocene period.Momose has shown that the Curie temperature of titanomagnetite in a solid solution series between TiFe2O4 and Fe3O4, seems likely to reflect the composition of associated magma and is taken as a clue for identification of tephra.Certain topics on tephrochronology hitherto carried in Europe and in Japan are introduced.