The lavas formed have been plagioclase ultraphyric basalts with large 4 cm crystals. The southern area of the island is formed from flat basalt layers from two eruptive phases, the second of which formed a caldera that has now eroded. The volcanic history of Wolf is complex, with at least two major eruptive phases. The volcano that formed Wolf Island is now extinct with last eruptions believed to have been 900,000–1,600,000 years ago, meaning the last eruptions occurred before the last eruptions on Darwin Island. Wolf Island is the southerly island on the lineament. There are currently two theories on the formation of the lineament and therefore Wolf island: the first is that magma rising from the mantle plume forming the main Galápagos Islands has been channelled towards the Galápagos Spreading Center alternatively there has been a separate rise in magma caused by stress in the ocean lithosphere by a transform fault. Like its near neighbor Darwin Island, Wolf is upstream of the magma plume, in terms of plate movement, that forms the main Galápagos Islands and does not fit in with the formation of those islands. Wolf Island is the remains of an extinct volcano that reaches a maximum 253 m (830 ft) above sea level, it is situated north west of the main Galápagos Island group on the Wolf-Darwin Lineament that extends from the Galápagos Platform to the Galápagos Spreading Center, a mid ocean ridge separating the Nazca and Cocos tectonic plates. It was previously known in English as Culpepper and Wenman and in Spanish as Los Hermanos ("The Brothers") or los Dos Hermanos ("the Two Brothers"). The group formed by Wolf and nearby Darwin Island is now known as Darwin and Wolf, Darwin–Wolf, or Darwin-Wolf. The name was bestowed by the English pirate William Ambrosia Cowley in 1684 and used for centuries thereafter. In English, the island was previously named Lord Wenman's Island or Wenman Island in honor of Philip Wenman, 3rd Viscount Wenman. He is also the namesake of Wolf Volcano on Isabela Island. Wolf is named in honor of the German geologist Theodor Wolf ( ), who published several important works on the geography and geology of the Galapagos Islands and mainland Ecuador. Another school of scalloped hammerheads at Wolf Island, Galápagos
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