Across
1
Where river meets the sea
4
Ridge of rock or coral near the surface
5
Line dividing two countries
6
Vast body of salt water
9
Land surrounded by water
Down
2
Largest hot desert in the world
3
Mountain that can erupt with lava
7
Long-term weather patterns of an area
8
Large slow-moving mass of ice
10
Wearing away of land by water or wind
11
Deep narrow valley with steep sides