On Friday I'm taking a very short road trip to Salt Lake City, Utah from Southern California to visit family. We will be on Highway 15 most of the way. I'm wondering if anyone has any ideas on geological/historical things to see along the way, particularly off of the 15 freeway in Nevada or Utah (from Vegas to SLC). I've taken the trip to Vegas many times so I'm familiar with everything from LA/OC to Vegas. Any ideas would be appreciated!