Across
1
Ridge of rock or coral near the surface
4
Imaginary line around the middle of Earth
5
Deep narrow valley with steep sides
6
Mountain that can erupt with lava
7
Largest hot desert in the world
8
Flat elevated area of land
9
Land surrounded by water
10
Wearing away of land by water or wind
Down
2
Largest ocean on Earth
3
Chain or group of islands