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 operates as the Hotel Alex Johnson. The "North by Northwest" appearance has been parodied in several venues. In "North by North Quahog", a 2005 episode of the animated series "Family Guy", Mount Rushmore's forested plateau was the location of the villain's home, and characters Peter and Lois are chased down the monument by Mel Gibson. In "Richie Rich", the Rich family's imitation of Mount Rushmore becomes the setting for the film's finale, echoing the finale of "North by Northwest". Alan Weisman, in his book "The World Without Us", suggests that the Mount Rushmore memorial could last up to 7.2 million