A narrow formation of rock that arches out into the water from the coast.

The source of a river.

A large, funnel-shaped depression in the ground caused by a cavern collapse.

All the streams that merge and flow toward the sea as a large river.

Narrow, sandy islands that lie off the coast of the mainland.

Natural ridges formed when water flow causes a river to drop some of its sediments along the edges of the rivers channel.

A joined stalactite and stalagmite.

A region of land drained by a stream or river system.

An isolated column of rock that forms when a sea arch collapses.

One of numerous streams that feed into a river at various points.

Calcium carbonate deposited by water droplets.

The sharp, steeple-shaped point of a mountain with three or more cirques.

A long pile of rocks deposited parallel to the shore, to prevent erosion.

A winding, looping curve in a river on flat ground.

Regions of the earth's surface where limestone is exposed and abundant.

The sediments carried by a stream.

A glacier-carved valley filled with seawater.

A lake formed when a sharp curve in a river is cut off from the rest of the river.

A spire-like mass of dripstone on the floor of a cave.

Natural acid found in rain and ground water that promotes chemical weathering of rocks.