Abstract
The Tertiary in the Tugawa basin, which seems to be closely connected with the oil bearing Tertiary in the Niizu nnd Kamo oil fields, includes three formations : the lower Tugawa, the middle, the Awaze, and the upper, the Tokonami., TheTugawa formation can be divided into two members : Kannonzawa conglomerate, the basal conglomerate of the Tertiary in this area, contains Comptoniphyllum-Liquidambar flora in its shaly parts, and Anadara daitokudoensis takeyamai, Paphia sp., in sandy parts; Hirotani green tuff, which has thick liparite sheets, may be correlated wuth the Takayanagi green tuff in the Kamo oil field., the Awaze formation, which has so-called "black shale" facies, overlies green tuff conformably and contains ill-preserved fossils, such as Chlamys miyatokoensis, Bursa cf., yabei, Olivella cf., iwakiensis in its lowest horizon, and Serripes laperousii, Lucinoma actilineata, behringensis, Panomga simotomensis etc., in the uppermost horizon., The greater part of teh Tokonami formation has "sandy shale" but it is difficult to distinguish from the upper part of the Awaze formation by lithological character only., Division of both formations is based upon the sight erosion surface and conglomerate between them., The above-mentioned fossils indicate that the age of the Tugawa formation is probably F2-F3, the Awaze formation is F3-G, and the greater part of the Tokonami formation is considered to belong to H (Pliocene) by lithological featers.,
