monument in 1980 to form modern-day Channel Islands National Park. Oil spill On January 28, 1969 an oil rig belonging to Union Oil experienced a blow-out off the coast of California. The resulting spill was, at the time, the largest oil spill to occur in United States territorial waters. Crews took approximately 11 days to seal the rupture using a cement plug, during which approximately of crude oil spilled into the Pacific Ocean, creating an oil slick with an area of about . Following the spill, tides carried the oil onto the beaches of the Anacapa, San Miguel, Santa Rosa and Santa Cruz islands. This spill had a large impact on native wildlife of the Channel Islands. Much of the islands' seabird population was affected, with over an estimated 3,600 avians killed. Meanwhile, seals, dolphins and other sea life died and washed ashore on both the islands and the mainland. This spill is the third largest oil spill in the United States, only surpassed by the Deepwater Horizon and the Exxon Valdez oil spills. It resulted in a expansion of the Department of the Interior buffer zone in the channel and contributed to the formation of the Environmental Protection Agency. The State of California Department of Oil and Gas noted 29 natural oil seeps between Point Conception and Rincon Point. The seeps were first noted by Father Pedro Font in 1776. Additionally, tar mounds are concentrated off the coast at Point Conception, Coal Oil Point, and Carpinteria. A natural oil seep also exists off the west coast of San Miguel Island. Finally, the distinctive odor of the petroliferous Monterey Shale is evident on the eastern end of Santa Cruz Island. The Chumash used the tar and oil from these seeps for caulking and adhesives. Geography The islands within the park extend along the Southern California coast from Point Conception near Santa Barbara to San Pedro, a neighborhood of Los Angeles. Park headquarters and the Robert J. Lagomarsino Visitor Center are located in the city of Ventura. The park consists of , half of which are under the ocean, and includes the islands of: San Miguel Santa Rosa Anacapa Santa Barbara Santa Cruz 76% owned by the Nature Conservancy, 24% by the National Park Service Climate According to the Köppen climate classification system, Anacapa Island has a Warm-summer Mediterranean climate (Csb). Geology Weaver describes the geologic province of Anacapia as consisting