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 Rushmore in popular culture years and thus be one of the longest-lasting human artifacts. Because of this enduring structure, it has appeared in some science fiction set in the distant future: In addition to in "Pilotwings 64", Mount Rushmore also appears: American composer Michael Daugherty's 2010 piece for chorus and orchestra, "Mount Rushmore," depicts each of the four presidents in separate movements. The piece sets texts by George Washington, William Billings, Thomas Jefferson, Maria Cosway, Theodore Roosevelt, and Abraham Lincoln. Alice Cooper references Mount Rushmore in his album DaDa on the song "I love America" with the words, "I love that mountain with those