Or "the lesson in volcanology": how to find in one place all kinds of lava, bombs, spatter cones, cinder cones, lava tunnels, rifts and cracks.
ou "la leçon de volcanologie" : comment trouver en un seul endroit, toutes formes de laves, de bombes, spatter cones, cinder cones,tunnels de lave, rifts et fissures.