107. On Some Fossils from the Hukaura Beds Nisi-Tugaru District, Aomori Prefecture, Northeast Honsyû

Abstract

During a short trip to several localities within Aomori Prefecture, the writers had a chance to visit the Hukaura beds, and to collect some fossils from the beds. Hitherto, the Hukaura beds have been known to be very young in aspect, but as to the geological age from fossil-content, nothing was known. This is due to the fact, that the Hukaura beds are very scanty in fossil content, and that to collect even a few fragments, considerable time is required. The fragments collected by the writers are briefly mentioned in this article in order that other authors in concern may get an idea of the kind of fossils the Hukaura beds contain.
The Hukaura beds, as worked out by S. SHIBAYAMA in his graduation thesis, is the youngest Neogene deposit found in Nisi-Tugaru District, and consists of soft pumiceous tuff, cross-bedded loose sandstone, coarse-grained sandstone, sandy conglomerate and rather calcareous sandstone, with some shale. The present fossils of the writers are from the calcareous sandstone and coarse-grained sandstone layers. The Hukaura beds unconformably overlie the next older Azigasawa beds, which in turn is conformable to the underlying Akaisi beds; the Akaisi beds are unconformable to the next older Tanosawa beds, which in turn unconformably overlie the lowest or Odose beds.