Geology

2. - Molten rock that erupts from a volcano and cools on the Earth's surface.
4. - The study of rock layers and their formation, used to determine the geologic history of an area.
6. - A landscape characterized by caves, sinkholes, and underground streams, formed by the dissolution of limestone or other soluble rock.
8. - The remains or traces of a once-living organism, preserved in sedimentary rock.
12. - A hollow, rounded rock that is lined with crystals or mineral deposits.
13. - A large, circular depression in a volcano's summit, formed by the collapse of the volcano after a large eruption.
14. - A naturally occurring inorganic substance with a definite chemical composition and crystal structure.
15. - A fracture in the Earth's crust where movement has occurred.

1. - The layer of the Earth between the crust and the core, composed mostly of solid rock that flows over long periods of time.
3. - A large section of the Earth's crust that moves due to plate tectonics.
5. - A coarse-grained igneous rock composed mostly of quartz, feldspar, and mica.
7. - A large ocean wave caused by an earthquake, volcanic eruption, or landslide.
9. - A rock or mineral that contains a valuable substance that can be mined and processed for economic gain.
10. - Small particles of rock, soil, or organic matter that accumulate in layers and form sedimentary rocks.
11. - Soil or rock that remains frozen for two or more consecutive years.