This view is the entrance to Blue Grotto Cave. Note the moss growing on the rock below the stairway. Most of the cavern entrances formed from the local collapse of the lava tube. The variation in the color of the rock wall reflects different mineral contents in the rock and the patina of salts and other minerals on the rock surface.

The URL is: https://gotbooks.miracosta.edu/gonp/labe12/6/2010/html/lava169.htm Last modified: 12/6/2010