A sedimentary rock made up of clay or silt
The largest division of geological time
A scientist who studies soil
A calcium carbonate deposit shaped like an upside down icicle formed on the floor of the cave
A theory that says Earth's outer layers are made up of moving parts
Thin layers of rock that lie at different angles
Principal of ________ is a theory that says sedimentary rocks on the bottom are older than rocks on the top
The study of the order and correlations of Earth's rocks
An era when dinosaurs existed; means middle life
A fossil that characterizes a particular period of time
Rock that has changed from another rock because of heat pressure, or a chemical reaction
Any remains, trace, or imprint of animal or plant life preserved in Earth's crust
A carbonate mineral with the chemical formula CaCO3
A person who explores caves
An era when trilobites, corals, brachiopods, early fish, and early amphibians existed; means "ancient animal life
An opening in Earth's crust where lava, cinders, ash, and gases come to the surface
A span of time within an era
Molten rock on the surface of the Earth