At the foot of the ridge, in a wide, natural basin glowed a ring of fire.

The area is a natural basin surrounded on all by high hills, water having nowhere to drain settles here after heavy rain.

A few miles farther on, they came to a great natural basin in the pass, a wide, level bowl.

Other dunes in the Americas form at the edge of a natural basin.

This meadow's a natural basin not yet filled level.

One of the stones had a natural basin with mosslike water plants lining it.

Twenty feet below, the converging waters gushed into a natural basin.

Here the run-off from the highest part of the rocks was caught in the natural basins and held there.

I vigne di Fessina are one of these natural basins, rich in their poverty.

A natural basin for boats existed at the mouth of the river.