2
A sedimentary rock made up of clay or silt
3
The largest division of geological time
5
A scientist who studies soil
6
A calcium carbonate deposit shaped like an upside down icicle formed on the floor of the cave
8
A theory that says Earth's outer layers are made up of moving parts
9
Thin layers of rock that lie at different angles
13
Principal of ________ is a theory that says sedimentary rocks on the bottom are older than rocks on the top
18
The study of the order and correlations of Earth's rocks
19
An era when dinosaurs existed; means middle life
21
A fossil that characterizes a particular period of time
22
Rock that has changed from another rock because of heat pressure, or a chemical reaction
24
Any remains, trace, or imprint of animal or plant life preserved in Earth's crust
25
A carbonate mineral with the chemical formula CaCO3
27
A person who explores caves
28
An era when trilobites, corals, brachiopods, early fish, and early amphibians existed; means "ancient animal life
29
An opening in Earth's crust where lava, cinders, ash, and gases come to the surface
33
A span of time within an era
34
Molten rock on the surface of the Earth