Paleozoic and Mesozoic geosynclinal strata in Japan have long been thought to be very thick and to form high angled homocline. Recent studies by KIMURA and others, however, show that those strata form small scale isoclinal folds with gently folded enveloping surfaces in a large scale, and that the strata are rather thin, less than several thousand meters. On the other hand, Upper Triassic conodonts have recently been found by IGO and others from the strata which have been thought to be of Paleozoic. The stratigraphic horizons shown by the fossils are consistent with the structural analysis by KIMURA and others. Strata, which change gradually to the Ryoke metamorphic rocks, contain the Upper Triassic conodonts and are probably covered conformably by the strata with the Upper Jurassic ammonoid. Weakly metamorphosed strata near the Sambagawa zone are overlain conformably by the Upper Triassic strata. Therefore, it became very clear that the Ryoke and Sambagawa “metamorphic” zones have suffered from the Cretaceous foldings as proposed by KOBAYASHI. The Paleozoic and Mesozoic strata in the Sangun-Yamaguchi and the Sambagawa-Chichibu zone were folded successively from the Late Permian to the Cretaceous time to form composite fold systems. On the other hand, strata in the Sambosan and the Shimanto zone were folded in each very short folding stage and formed isoclinal folds with very short wave-length. When the Triassic subduction zone was situated to the oceanic side of ancient Japan, the Sambosan zone-non-fold zone-, the Kurosegawa-fold zone-, the southern Yamaguchi-northern Chichibu-non-fold zone-, and the northern Yamaguchi-Hida zone-intense fold zone are arranged from the oceanic to the continental side. The distribution of the deformation zones has not been produced only by the compression due to the subduction of oceanic plates.
The phylogeny and mode of evolution of a Liassic oyster Gryphaea have been studied by many European and American outstanding evolutionists since TRUEMAN's (1922) classical interpretation of its morphological change. For these fifty years many useful ideas and methods in the study of morphogenesis, biometry, autoecology and functional morphology were introduced into paleontology through this material. In this report some of these works are reviewed and evaluated, and what is suggested to general evolutionary paleontology is considered.