Clarion Island (), formerly Santa Rosa, is the second largest, westernmost and most remote of Mexico's Revillagigedo Islands. The island is located west of Socorro Island and over from the Mexican mainland. It has an area of and three prominent peaks. The westernmost and tallest peak, Monte Gallegos, is high. The central peak is called Monte de la Marina, , and the eastern peak Pico de la Tienda . The coasts are backed by perpendicular cliffs, high, with the exception of the middle part of the southern coast in the vicinity of Bahía Azufre (Sulphur Bay), which is the location of a small military garrison with a contingent of 9 soldiers. Two small and at least temporarily brackish pools are the only source of fresh water; even these may dry up in summers with little rain. Clarion can only be reached by sea, which from Mexico takes 30 hours. History No signs to indicate prehistoric human activity have ever been found on Clarion Island. It was visited in late 1542 by the Spanish navigator Ruy López de Villalobos, but with the exception of a possible re-sighting of the Revillagigedos by Juan Fernández de Ladrillero before 1574 and a short-lived residence by the adventurer Martín Yáñez de Armida on the island he later renamed Socorro (1606), the archipelago was neglected by the Spaniards. Joris van Spilbergen's sighting of the whole group in December 1615 seems not to have been noted in Spain or its American colonies. Clarion was sighted again by the English privateer George Shelvocke on the Speedwell, August 21, 1721. The name of the island goes back to the American brig Clarion, Capt. Henry Gyzelaar, who was engaged in the North Pacific trade around 1820. The Handbook of Selected Pacific Islands (1959), by Edwin B. Doran, observed that "Clarion has never been occupied by man for more than a few days at a time", adding that "there are no facilities of any sort at present." Ecology As the topography of Clarion lacks any prominent peaks that could induce rains like Cerro Evermann on Socorro Island, the island is semiarid to arid all over. Consequently, the whole of the island is covered in shrubland, grassland and Opuntia cacti. Far away from land, endemic taxa are fewer than on Socorro but like there mainly consist of landbirds and plants. Rabbits and feral sheep are found on the island and have caused