Miocene Microbiostratigraphy of West Honshû, Japan

Stratigraphical and paleontological studies of geographically isolated Neogene areas in West Honshû, Japan, has lead to the establishment of two large provinces, each of which is subdivided into subprovinces from their respective characteristics. Detail field and laboratory work on each of the areas revealed that the frequency and faunal displacement of the smaller Foraminifera yielded from the respective characteristic lithological units are widespread and exhibit a sequence expressible in the form of stages, zones and faunules, which are introduced and described in this article.
The recognized time-rock units as well as lithologic units and their respective smaller foraminiferal faunas are described, discussed and applied to the Neogene deposits of West Honshû, and are compared with known similar domestic units and the results are brought into comparison with the Tertiary sequence of Northwest America and the Indo-Pacific region with which correlation is attempted. Although differences in the respective smaller Foraminifara of the three remote regions just mentioned exist, there are found remarkable coincidences in their sequence, characteristic features reflected by them, and noteworthy similarity in the association or assemblage elements of the respective regions.
Periods of volcanicity as related with the lithological units and differentiation during the faunal sequence and the whole as associated with the growth of the respective sedimentary basins studied by the writer in West Honshû, reveal that there exists intimate relationship with the establishment and significance of the respective time-rock units introduced in this work.
The new species of smaller Foraminifera obtained during the past few years are described and illustrated in this work, and with regard to previously known forms records of their occurrences from the respective lithological and time-rock units are given in table form.