A fossil Sassafras leaf collected by Dr. S. MABUTI from the Woodwardia zone (Upper Eocene) of the Isikari Coal Field, is quite identical with Sassafras alaskanum HOLLICK, described originally by HOLLICK from Alaska. The occurrence of Sassafras in the Woodwardia zone has a great significance on the consideration of the past migration of the genus and on the correlation of the Woodwardia zone with the plant beds of Alaska.
The distinctive winged fossil seed, collected by the present writer from the Kyûsin Coal. Mine, Kankyô-Hokudô, Tyôsen, is quite similar to and only slightly differs from those of the seeds of Cedrela, especially one of its existing species C. mexicana ROEMER of Mexico and West Indies. It resembles more closely Cedrela pteraformis BROWN from the Latah formation of Spokane, Washington, United States of America, both being almost identical in every respect. The present fossil is now provisionally referred to the American fossil species. This is the first record, of fossil Cedrela from East Asia, and the plant fossils found in its association from the Cedrela bed are listed in the table on p.225. On these fossils, the Cedrela bed is believed to be nearly contemporaneous with the Engelhardtia bed (Miocene) of Kankyô-Hokudô, Tyôsen.