Across
- 3. a mountain or hill through which lava, rock fragments, hot vapor, and gas are being or have been erupted from the earth's crust
- 4. The law that states the oldest rocks are on the bottom and the youngest rocks are on top
- 6. Determining age by using radioactive isotopes to find a more exact date
Down
- 1. Where younger layers crosscut older layers, such as a volcanic rock vein cutting through older sedimentary layers
- 2. The preserved remains or traces of organisms that lived in the past
- 5. Means to last or retain certain characteristics over a long period of time