This cross-section shows the parts of a volcano. A conduit feeds magma to the surface. Near the surface, the gas expands and fragments the lava into ash. Some magma passes through dikes to feed vents. Some magma intrudes parallel to layers to make sills.
Macdonald, G.A., 1972, Volcanoes: Englewood Cliffs, New Jersey, Prentice-Hall, p. 510.
Discovering Northwest Volcanoes: A Learning and Activity Book; 1993; by Nancy Field and Sally Machlis;
Published by Dog-Eared Publications, Corvallis, Oregon and Middletown, WI. P.O. Box 620863, Middletown, WI 53562-0863, USA. $3.95; 32p.
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