The White Tail Ridge Formation in Oregon preserves Paleogene fossils and records river, delta, and shallow-marine deposition along the edge of an Eocene basin in southwestern Oregon. Its conglomeratic layers contain clasts from volcanic, plutonic, metamorphic, and sedimentary terranes, indicating tectonic uplift in the Klamath Mountains and surrounding areas. Marine invertebrates, plant remains, and carbonaceous deposits preserved in the formation point to a warm, humid Paleogene environment. Within the regional rock sequence, it lies above older lower Eocene strata including the Tenmile Formation and is overlain by the Tyee Formation.