The ship was racing down smoothly towards the mouth of a steep-walled valley he'd selected as the most promising landing point barely a minute before.

Dawn broke as they came out of a narrow gorge into a steep-walled valley.

The sun was setting now behind the reefs, limning their karst topography of ragged peaks and steep-walled valleys.

The brown landscape is a result of ice scouring, which left virtually no vegetation on the steep-walled valleys.

The chopper rose out of the steep-walled valley and skimmed southwestward over the mesa tops.

Besides rock-covered glaciers around mesas, the region had many steep-walled valleys with lineations-ridges and grooves-on their floors.

Downstream of the falls there is a narrow steep-walled valley, with cascades around large blocks that have fallen in from the sides.

The mod drifted down into the arms of a steep-walled valley.

Besides rock covered glaciers around mesas, the region has many steep-walled valleys with lineations-ridges and grooves-on their floors.

The region is notable for its maze-like system of deep, steep-walled valleys.