Chaos occurs often in fluid, namely in water and air. Even the solid material in the earth’s crust and the ‘Solid Earth’ have some fluidal nature. This can happen in nature especially over a very long time.

Chaos occurs commonly in human society also. The combined effect of these two kinds of chaos, natural and social chaos, can be a deadly complication. Laws (rules) in nature can be distinguished into two kinds. One is the principle (axiom) which does not demand demonstration (proof). Another is a law (rule) which is induced from the principles. On the other hand, some so called rules which is often adapted in ‘scientific’ works are, in reality (fact), mere ‘general tendencies’. In these cases, possible occurrence of chaos also must not be ignored. Many ‘general tendencies’ in nature, however, have often been dealt with as ‘definite rules (laws)’in geosciences. A typical example is the use of the ‘correlation rule’ between the length of an active fault and the strength of an earthquake for pre-estimation of the earthquake strength around atomic stations in Japan.

Seeming regression lines of data distribution have been applied for estimation without any examination of the real geological causes of the data variance.

The Nyunokawa Formation is submarine fan deposits which constitutes the southernmost part of the Cretaceous Hidakagawa Belt of the Shimanto Superbelt in the Kii Peninsula. This formation was used to be assigned late Campanian radiolarian age. Later, it was pointed out that the Eocene Otonashigawa Group is very similar to this formation in litho-stratigraphy, geologic structure and the composition of coarse clastic rocks. But no supporting fossil evidences had been reported from the Nyunokawa Formation so far. Since the late Campanian fossil localities have been reinterpreted as the tectonic blocks of the Cretaceous Ryujin Formation, any evidence-based age constraints for the Nyunokawa Formation were lost.

Radiolarian fossils have not been detected from the matrix of the Nyunokawa Formation, but instead upper Cretaceous to Paleocene radiolarian fossils were newly found from mudstone gravels in the conglomerate of the uppermost horizon of the Nyunokawa Formation, suggesting a Paleocene depositional age. This first reliable radiolarian ages from the gravels precludes a possibility of Cretaceous age. Therefore, the Nyunokawa Formation should be correlated to the Otonashigawa Group. During sedimentation of the Otonashigawa Group, submarine fan had been formed twice in the Paleocene and in the Eocene. It is also notable that gravels of the conglomerate in an accretionary prism are composed of three types; 1) gravels eroded on land; 2) gravels originating from submarine channel erosion of older accretionary prism; and 3) syn-depositional rip-up clasts of submarine fan deposits.