The stratigraphy and paleontology of the Cenozoic deposits developed in the Joban coal-field, northeast Ibaragi and southeast Fukushima Prefectures, have already been studied by many authors. Since C. KOCHIBE (1883) reported on the occurrence of fossil molluscs from the rocks building the upper part of the Tertiary deposits, many authors described the large marine molluscan fauna occurring from the different lithologic units in the coal-field.
Since 1948, the writer has been engaged in the stratigraphical and paleonto• logical studies of the Tertiary formations and a great number of molluscan fossils has been accumulated in his collection. From the result of the writer's works on the stratigraphy of the central part of the Joban coal-field, the strati• graphic sequence of the rocks given in Table 1 (HIRAYAMA, 1960, 1961)- In the present article, the writer describes the new species of molluscan fossils which he
collected from the upper horizon of the stratigraphic sequence of the Joban Tertiary. Remarks on the molluscan fauna, especially concerning the characteristic assemblages and other details will be mentioned in another opportunity. The present article is the writer's second report on the paleontology of the ]oban Tertiary, and in the previous one (HIRAYAMA, 1955) was given a detail considera• tion of the fauna! assemblage of the Asagai formation, late Oligocene in age.

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