Unconformity of the Pre-Sakamotozawa Stage (Pre-Sakmarian) in the Kitakami Mountainland, Northeast Japan

Abstract

1) In the Kitakami mountainland, Pseudoschwagerina begins to appear in the Sakamotozawa stage, together with a number of remains of Brachiopods, corals, calcareous algae, etc., of definite Permian type (including Artinskian)., This indicates that the appearance of Pseudoschwagerina means the dawn of the Permian age., 2)The Pseudoschwagerina zone lies unconformably on the inclined older formations separated by a visible erosion surface which the present writer proposes to call "The Pre-Sakamotozawa un-conformity"., The whole structural amount due to intense disturbance before the Sakamotoza stage is provisionally called "The Setamai folding"., 3) The Setamai folding is related in age to the Marathon Orogeny of North America and Kun-mingian of South China and Indo-China, and also equivalent to STILLE'S "asturische Phase"., 4) True Trlticites or Uralian fauna (s., s., ) is not yet known to occur in Japan (including Tysoen) and its adjacent lands., This fact may suggest the probable existence of hiatus of considerable amount between Carboniferous and Permian.,