The Table Mountain Formation is at the crest of the Jacumba Mountains which are largely underlain by the Cretaceous Peninsular Ranges batholith. The Formation is an immature sandy conglomerate which was deposited by intermittent streams in hills of granodiorite that had 70 meters of relief. Cretaceous, Eocene, and Tertiary ages have been suggested for the Formation. Correlations with Eocene conglomerates in Arizona and coastal California have been proposed. Paleocurrent data indicate that the source terrane of the Table Mountain Formation is to the northwest and northeast. This study establishes the Jacumba Mountains and the nearby Coyote Mountains as a major part of the provenance for the metamorphic and igneous clasts in the Table Mountain Formation. The Formation is overlain by Miocene volcanic flows and Miocene volcanic clasts are contained in the Table Mountain Formation; this establishes a Miocene age for the Formation. Similarity with the Miocene Split Mountain Formation of the western Colorado Desert suggests a correlation between these stratal units. Uplift of the Jacumba Mountains in the Late Miocene is suggested based on correlation with the Miocene Split Mountain Formation, which has a marine facies, and the absence of the Pliocene Imperial Formation in the region.
