Volcanoes and volcanic rocks. 

 - videocassette (VHS)(20 min.) :  sd., col. 1/2 in. 
<br/><br/> A short film which looks at several different kinds of volcanoes including an oceanic volcano as well as a collection of volcanic rocks that are formed from volcanic activity. 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Rocks, Igneous--Study and teaching.<br/>Volcanoes--Study and teaching.