The progressive upward changes in the member would reflect backwearing of the scarp and probably also reduction in relief of the source area.
A suballuvial bench may have formed through retreat of the western fault scarp.
This scenario requires extensive scarp retreat to produce a suballuvial bench for a fan whose apex was 30 km to the west.
The reserve comprises a species-rich coastal scarp forest (2611 ha) set in a mosaic of coastal grassland and rocky granitic outcrops (1277 ha).
The sedimentary breccias were probably formed from talus and/or other types of colluvium that were shed from the ring-fracture fault scarp of the caldera.
This is commonly because of rapid burial of the fault scarps under contemporaneous lava flows.
The conglomerates that predominate in the lowest parts of both groups imply the presence of fault scarps at the surface.
Birds of prey nest on rock scarps and in canyons that are difficult to access.
