Mount Rushmore community. Recent pine beetle infestations have threatened the forest. Mount Rushmore is largely composed of granite. The memorial is carved on the northwest margin of the Black Elk Peak granite batholith in the Black Hills of South Dakota, so the geologic formations of the heart of the Black Hills region are also evident at Mount Rushmore. The batholith magma intruded into the pre-existing mica schist rocks during the Proterozoic, 1.6 billion years ago. Coarse grained pegmatite dikes are associated with the granite intrusion of Black Elk Peak and are visibly lighter in color, thus explaining the light-colored streaks on the
Mount Holyoke Range State Park Mount Holyoke Range State Park Mount Holyoke Range State Park is a state-owned, public recreation area encompassing the eastern half of the Holyoke Range in the Pioneer Valley region of Massachusetts. The state park is adjacent to J. A. Skinner State Park, which occupies the western half of the Holyoke Range. Both are managed by the Massachusetts Department of Conservation and Recreation. Resource Management Plan: Mount Holyoke Range Planning Unit, Department of Conservation and Recreation, July 2013, p. 16 Park trails are used for hiking, horseback riding, and cross-country skiing. Trails include sections of the long-distance Metacomet-Monadnock and Robert Frost