While traveling west from Denver, there is a stretch of Interstate 70 between Green River and Salina Utah that is called the San Rafael Swell. It is a dome-shaped anticline (or upward fold in the earth's surface) that consists of sandstone, shale, and limestone that was pushed up millions of years ago. Since that time, erosion has played a major part in creating the topography of the Swell.

For more information about the San Rafael Swell, please click on the following link:

http://www.sanrafaelswell.org/ ... (more)