It is the only valley worldwide which is formed by basalt boulders sitting on a clay base.

Beyond the water lay a jumble of immense basalt boulders.

The designs were scraped into a basalt boulder by Native Americans perhaps 12,000 years ago.

The mountain is honeycombed with caves and is covered in many large basalt boulders.

The trees were cleared, but they left the basalt boulders intact.

Monument 21 is a basalt boulder in a sugarcane field.

They passed another entrance guarded by a large basalt boulder.

The entrance to the building was blocked by a large basalt boulder.

A four-ton basalt boulder stands in the middle of the floor.

He selected a basalt boulder and sat on it.