Keywords: An Igneous Sill Intrusion in Yellowstone National Park Wyoming USA.jpg basaltic sill showing columnar jointing at the Yellowstone River in Yellowstone National Park in Wyoming USA 2006-08-27 http //pixabay com/en/erosion-yellowstone-national-park-226655/ Brigitte Werner werner22brigitte on Pixabay http //pixabay com/en/users/werner22brigitte/ 44 899273 -110 390134 226655 LicenseReview http //pixabay com/en/erosion-yellowstone-national-park-226655/ JurgenNL 2014-01-23 Uploaded with UploadWizard Sills geology Columnar basalts in Yellowstone National Park Geology of Yellowstone National Park Images from pixabay |