The Shiose-no-misaki Sandstone and Conglomerate SSC in the Oga Peninsula is believed to represent SSC in the Oga Peninsula is believed to represent SSC a latest Eocene to early Oligocene marine succession located on the back-arc side of NE Japan. This unit is, however, isolated from adjacent units, and its stratigraphic position has remained in debate. On a sea cliff adjacent to the type locality of the SSC, surface soil and vegetation recently slid down by heavy rain to disclose a succession that contains the SSC, surface soil and vegetation recently slid down by heavy rain to disclose a succession that contains the SSC SSC and the SSC and the SSC overlying early Miocene non-marine unit correlative to the Daijima Formation. The SSC at the new outcrop comprises scoria-SSC at the new outcrop comprises scoria-SSC lapilli tuff and parallel to wavy laminated fi ne sandstone, both of which are intruded in dike by thinly bedded pumicelapilli tuff, pumice-bearing tuff, sandstone and mudstone as observed also in the adjacent SSC. The overlying succession is SSC. The overlying succession is SSC over 20 m thick and dominated by massive very coarse to coarse sandstone with a basal, normally graded cobble to granule conglomerate 1.3 m thick. Pumice lapilli tuff occurs between the conglomerate and the overlying sandstone with a thickness of 30 cm, and tuffaceous mudstone and coaly shale beds 20 to 30 cm thick occur in between the sandstone. The conglomerate and sandstone commonly contains gravels and/or sand grains of dacite welded tuff derived from the adjacent early Miocene Hokakejima Dacite the lowest unit of the Daijima Formation . Pumice lapilli tuff in the upper unit is 20 Ma in FT age, suggesting slightly younger than the FT ages of 22-21 Ma for the Hokakejima Dacite. The pollen assemblage from the SSC likely refl ects a cool temperate climate that might have prevailed in accordance with Oligocene to Early Miocene cooling. We thus suggest the SSC is a part of the late Eocene to early Oligocene Monzen Formation extensively distributed to the west of SSC is a part of the late Eocene to early Oligocene Monzen Formation extensively distributed to the west of SSC Cape Shiose-no-misaki.
