The mountain is composed of a geologic unconformity between two separate rock formations. The valley formation is dated to the Late Pliocene and early Pleistocene uplift unconformity. An angular unconformity (an uneven gap in the geologic record) followed. They lie upon an angular unconformity which cuts across pre-basin strata. A second unconformity was created after the Permian sea retreated. There is an unconformity at the Pliocene base. Erosion returned, forming a third unconformity. These deposits occur below, across and immediately above the unconformity. A fourth unconformity was created by a period of erosion. This large unconformity indicates a long period for which no deposits are present. There are three types of unconformities&colon; disconformity, angular unconformity, and non-conformity. The record of the Cenozoic activity begins above this unconformity. The Campanian follows after a pronounced unconformity. This event is synchronous with the major unconformity above. A type of unconformity called a disconformity was formed.