Valles Caldera National Preserve (väˈyās) [key], 88,900 acres (36,000 hectares), N N.Mex.; est. 2000. Formerly part of the vast, privately owned Baca Ranch, the preserve lies at the heart of the Valle Grande (Jemez) Mountains and encompasses most of a 12–15 mi- (19–24 km-) wide circular caldera, a sunken volcano formed by the collapse of volcanic domes after two massive eruptions about 1.6 and 1.2 million years ago. The basin is some 3,000 ft (915 m) deep, measured from the surrounding rim, which encircles several lava-dome mountains. The landscape is mainly a mixture of grasslands and forested mountains, cut by numerous streams. Like other calderas, it has hot springs, gas vents, and other volcanic features. Wildlife include 17 threatened or endangered species such as the Mexican spotted owl, goshawk, Jemez Mountains salamander, and Rio Grande cutthroat trout. The preserve also is home to elk, mule deer, black bears, mountain lions, coyotes, bobcats, and other mammals, and golden and bald eagles and other birds.
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