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 Tom State Park canoeing on Mount Tom Pond, hiking the nearly one-mile-long loop trail that ascends Mount Tom to the observation tower, and picnicking. Mount Tom State Park Mount Tom State Park is a public recreation area lying south of US Route 202 in the towns of Washington, Litchfield, and Morris, Connecticut. The state park occupies on the southwest shore of Mount Tom Pond and is home to the Mount Tom Tower, which was listed on the National Register of Historic Places in 1993. It is managed by the Connecticut Department of Energy and Environmental Protection. The park is one of the oldest