. Bulletins of American paleontology. Bulletin 331 middle Miocene), Shiobara (middle middle Miocene to late Miocene), and Omma-Manganji (Pliocene and early Pleistocene) faunas are of the cold-water type. For the Neogene and Earh Quaternary naticids, 1 have inferred their paieociimatic preferences from their geographic distributions (Text-figs. 3, 4. 5) and their associated faunas. The geographic distributions of modem populations of extant species are used to rein- force those inferences, and are mainly based upon the data of Kuroda and Habe (1952) and Higo (1973). Japanese Neogene and Early Q
. Bulletins of American paleontology. Bulletin 331 middle Miocene), Shiobara (middle middle Miocene to late Miocene), and Omma-Manganji (Pliocene and early Pleistocene) faunas are of the cold-water type. For the Neogene and Earh Quaternary naticids, 1 have inferred their paieociimatic preferences from their geographic distributions (Text-figs. 3, 4. 5) and their associated faunas. The geographic distributions of modem populations of extant species are used to rein- force those inferences, and are mainly based upon the data of Kuroda and Habe (1952) and Higo (1973). Japanese Neogene and Early Quaternary naticids are classifiable into the following three paieociimatic pref- erence t>pes: C (cold-water). \V (warm-water) and Bt (broad temperature tolerance). Species of the C and W t\ pes li\ cd in areas influenced b> cold-water (Oyashio) and warm-water (Kuroshio) currents, respectively. Species of Bt type lived in both warm and cold waters in Japan. Both the C and W types are further divisible into two subtypes on the basis of their paleogeographic distributions: Ce (Cold-water endemic) and Cw (Cold- water widespread), and We (Warm-water endemic) and \\w (Warm-water widespread). Species of the Ce and We types were endemic to Japan and adjacent areas. Species of the Cw and Ww types were more widespread: Cw species also lived in the arctic region, and Ww species in the East Indies and farther south. In the following discussion, I divide the Neogene and Early Quaternary into four stages: early Miocene, earh middle Miocene, middle middle Miocene to late Miocene, and Pliocene and early Pleistocene. There is a distinct difference in the molluscan faunal compo- sition of each stage. Paleogene Paleogene naticids are known from the Ryukyu Is- lands, from northern Kyushu and from the Joban coal field of northeastern Honshu, where they are repre- sented by three Eocene and four Oligocene species. No Paleoccne naticids are known in Japan. Even though marine Paleogene deposits
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