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 Greylock State Reservation offers overnight accommodations and meals during non-winter months. The reservation's of trails for hiking, mountain biking, back-country skiing, snowshoeing and snowmobiling include an section of the Appalachian National Scenic Trail and the historic Thunderbolt Ski Trail. Primitive camping is available for backpackers at either the Mount Greylock Campground or remote trailside backpacker shelters, all of which are only accessible by foot. Hunting is permitted in season. Mount Greylock State Reservation Mount Greylock State Reservation is public recreation and nature preservation area on and around Mount Greylock, the highest point in the state of Massachusetts. The park covers some in the