How Volcanoes Work

 Image Described in Caption
 Palagonite tuff -- This palagonite tuff contains very small small fragments of basalt glass together with larger fragments of broken basaltic rock in a matrix of yellow-brown palagonite. The deposit forms the walls of a tuff ring located on Tenerite, the Canary Islands. The distinct bedding (layering) of the deposit most likely represents specific eruption cycles from the adacent tuff ring. Courtsey of Peter Francis.