1. Large, ancient landmass that was composed of all the continents joined together

2. Theory that the Earth’s crust and upper mantle are broken into plates that float and move around on a plastic-like layer of the mantle

3. Wegener’s hypothesis that all continents were once connected in a single, large land mass that broke apart about 200 million years ago and drifted slowly to their current positions

4. Hess’s theory that new seafloor is formed when magma is forced upwards toward the surface at the mid-oceanic ridge

5. Currents in Earth’s mantle that transfers heat in Earth’s interior and is the driving force for plate tectonics

6. Motion of the Earth’s surface as it shifts downward relative to a datum such as sea=level

7. Indicates a border

8. Formed when two sections of Earth’s crust is colliding – coming together

9. Forms where lithospheric plates are moving away from each other.

10. Boundary between two lithospheric plates that are sliding past each other.

11. Long crack that forms between tectonic plates moving apart at plate boundaries

12. Fracture that occurs when rocks change their shape by breaking can form as a result of compression, being pulled apart by shear

13. Area in which one lithospheric plate slides under another, occurs at converging plate boundaries

14. A chain of mountains or hills that form as continuous elevated crest for some distance

15. Depression in the ground, generally defined by being deeper than they are wide.

16. Plastic-like layer of the Earth on which the lithospheric plates float and move around

17. Rigid layer of Earth about 100 km thick, plates moving apart at plate boundaries

18. A physical map showing vertical features with a drawing such as shaded mountains

19. Features of a land area caused by differences in elevation.

20. A map that shows the shape and elevation of the land surface using contour lines, and shows other land features using symbols and colors

21. On a map, lines that connect point of equal elevation above sea level.

22. Height above average sea level

23. Distance between contour lines on a topographic map

24. A permanently affixed mark that establishes the exact elevation of a place; used by surveyors in measuring site elevations