Much of the valley is characterised by basaltic rock.
The similarity in basaltic rocks may indicate they have the same source.
The walls were smooth and appeared to be composed of a black, basaltic rock.
They followed Lewis for more than two hours, turning into a wide canyon flanked by black basaltic rock.
Generally, the areas having trap or basaltic rock are prone to earthquakes.
Leaving the presbytery, the Professor took a road through an opening in the basaltic rock, which led far away from the sea.
It is the second largest impact crater in basaltic rock in the world.
The larger part are made from basaltic rock and gabbro.
Black in the dark basaltic rock gaped a cave mouth.
These shapes were formed by blocks of rudely-carved basaltic rock.