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 Spokane State Park Mount Spokane State Park Mount Spokane State Park is a public recreation area located in the Selkirk Mountains, northeast of the city of Spokane, Washington. The state park surrounds Mount Spokane and other peaks including Mount Kit Carson, Beauty Mountain, and Quartz Mountain. The park receives of snow annually and is home to Mount Spokane Ski and Snowboard Park as well as an extensive system of trails for hiking, biking, and horseback riding. As of 2018, Washington State Parks reported its acreage as , making it Washington's largest state park, slightly ahead of Riverside State Park () which lies 23