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 Tamalpais State Park Mount Tamalpais State Park Mount Tamalpais State Park is a California state park, located in Marin County, California. The primary feature of the park is the Mount Tamalpais. The park contains mostly redwood and oak forests. The mountain itself covers around . There are about of hiking trails, which are connected to a larger, network of trails in neighboring public lands. The park received 564,000 visitors in . Muir Woods National Monument is surrounded by the state park. From the peak of the mountain, visitors can see up to , in a view that encompasses San Francisco, most of the