Across
- 1. A sharpened reed used to press markings into clay tablets.
- 4. A mixture of copper and tin; used to make stronger tools.
- 5. A picture or drawing that represents a word or idea.
- 7. ocean ridge An undersea chain of mountains that is part of a long system of underwater mountains.
- 8. A device that reflects sound waves off underwater objects and records the echoes.
- 9. A type of writing made up of wedge-shaped markings.
Down
- 2. The process by which crust sinks back into the mantle at a colliding plate boundary.
- 3. A deep undersea valley where crust sinks towards the mantle.
- 6. floor spreading The process by which molten material adds new crust below Earth's bodies of water.
- 8. A person who specializes in writing and serves as a record keeper.