Abstract
Tertiary deposits are extremely rare in the western part of Tyosen Peninsula while occur in several isolated areas of very limited extension along the eastern coast. The east coast Tertiaries are partly of marine and partly of terre-trial origin, and there are a number of coal-fields where coalbearing formations are rich in plant fossils, as in the environs of the town Hokô in Keisyô-hoku-dô, Tusen coal-mines in Kôgen-dô, Tyôhôri coal mines in Kankyô-nan-dô, Kissyû-Meisen district, Ranan, Seikirei, Kainei, Kokangen and Agoti, all in Kankyô-hoku-dô; especially the last three fields are situated in the extreme north of the peninsula and farther north there is the Konsyun coal-field which already lies in the confine of Manchoukuo.
Recently the present writer made a large collection of plant fossils in the Tusen formation of the Tusen coal-mines, the Kantindo of Kantindo and Hugandô, both in the Kissyu-Meisen district, and the Engelhardtia-bed of Ryulaokudo of the Kokangen coal-mines. The plant fossils from the Kantindo formation is listed on table II and those from the Engelhardtia bed on the table V. The Kantindo flora is believed to be nearly contemporaneous with that of the Tigano-ura plant beds of Siogama and that of Nenosiraisi, both near Sendai; the plant beds of Siogama belong to the Saboyama group. The flora of the Engelhardtia bed is somewhat older than the Kantindo flora; both are Miocene in age, none being Palaeogene.
