Abstract
Well- developed involutions are observed on the boundary between volcanic ash and frost shattered rock fragment layers to the northeast of Mt. Takamori (1220m) in the central Kitakami Mountains. According to the radiocarbon ages (Endo 1977, Inoue 1978) of Koiwai Pumice between the two layers, the involutions were formed after 13, 000- 16, 000 y. B. P. under cold climate.
