One common fossil in the Wasatch Mountains, which you saw in the section introduction, is of an organism called crinoids. Crinoids lived in ancient shallow seas. When they died, their bodies fell down to the bottom of the seafloor and became preserved as fossils in the layers of mud and other sediments. Over time, those mud and sediment layers hardened into solid rock while the fossils remained intact.
a living crinoid



Now, millions of years later, hikers in these high Utah mountains can find evidence of sea animals that lived there at one time. The crinoid fossils are found in many of the rocks that make up the mountains—evidence of what ancient environmental conditions were like. How do you think they got from the ocean floor to the mountains?