friends—just who was born first. The same is sometimes true for rock layers. Relative Ages Hands-On Activities Real-World Question Can you determine the relative ages of rock layers? Materials paper pencil Goals Interpret illustrations of rock layers and other geological structures and determine the relative order of events. Procedure 1.. 5) Paleontologist - A scientist who studies fossils and ancient life 6) Sedimentary Rock - Rock made of layers of tightly packed sand and clay 7) Sandstone - A type of sedimentary rock that is made of sand 8) Trace Fossil - A fossilized sign that a plant or animal once lived in an area (i.e. footprints, coprolite). "/>Rock layers and fossils worksheet