Two kinds of "breccias" can be distinguished on the basis of the foraminiferal fossil content and the lithology in the Shiiya and Nishiyama Formations. The distribution area of the "breccias" and the dominant kind of them shift with the lapse of time.
"Disturbed" deposits, which can be discerned by using CLUSTER, are mostly associated with occurrence of "breccias". Characteristics of them indicate that a part of them corresponds to olistostromes.
The direction of the paleoslope inferred from dips in the "disturbed" deposits is harmony with the decreasing direction of the sand content and the thickness of "breccias".