土佐國佐川盆地河内ケ谷統の逆轉構造に就いて

抄録

The Kochigatani series may be classified in descending order as follows : 3) Upper Part consisting chiefly of shale and sandstone to which subangular pebble bearing conglomerate is added., Pseudomonotis ochotica (KEYSERLING), its varieties and Pseudomonotis obsoleta KOBAYASHI occur in the upper shale and sandstone ; sandstone in which Pseudomonotis ochotica densistriata TELLER is crowded marks off a horizon below the preceding ; and the stratigraphic relation on the conglomerate containing Pseudomonotis ochotica acuticostata TRENCHMAN with the two other fossil beds is still uncertain., 2) Middle Part composed of shale, sandy shale and sandstone in which small flakes of mica are commonly scattered., This contains the Halobia (c), Pecten (b) and Myochoncha (a) beds probably in the order of superposition mentioned here., 1) Lower Part consisting mainly of hard massive sandstone in which conglomerate and conglomeratic sandstone are intercalated., The conglomerate contains pebbles of quartz-porphyry ; and the sandstone yields Avicula and many other fossils., Although the base of the series is unexposed in the basin, the lower and middle parts can be safely correlated to the Carnic B and C fossil beds of the Hirabara formation in the Mine Series in the Province of Nagato., The Pseudomonotis obsoleta zone, on the other hand, occurs above the Pseudomomotis ochotica densistriata zone in the Saragai formation in Rikuzen., If the latter zone is Upper Noric as current opinion holds, the former may be either uppermost Noric or possibly even lowest Rhaetic., The Kochigatani series is a thin formation, no more than 230 meters, which is completely overturned and folded intensely (see Profil)., And it is capped by the Permo-Carboniferous Upper Chichibu group., The group combined with the series forms a Decke which was ridden over the late Jurassic and early Cretaceous formations from the North., The contortion of the series is due to the shearing along the thrusting plane., While SHIMIZU once reported Proarcestes from a siliceous shale at Yamaguchi, there is no exposure of such a rock at this locality and furthermore the Kochigatani series does not contain cherty rocks at all.,