Along the highways of Missouri, you often see weeping limestone faces -- like the one shown above -- due to the porous nature of this sedimentary rock. These seeps can be especially beautiful when they freeze in the wintertime, forming dripping white icicles instead of appearing as dark streaks.
Driving through the canyons of Utah, rock layers sometimes appear vertical instead of horizontal due to uplift (see photo above for an example of this in California).
And if you are exploring the Big Island of Hawaii, some of your intended highways may have been covered by lava flow – a prime example of geology in action!
Learn more about U.S. geology by visiting the United States Geological Survey or drop by the Association of American State Geologists and click on the map to visit each state’s own Geological Survey.