Mount Rainier is a stratovolcano, or more commonly known as a composite volcanoe. Stratovolcanoes are usually symmetrical, cone shaped and built of alternating layers rocks. Composite volcanoes normally have a crater at the summit which has a central vent. where all the lava flows out of and then hardens strengthening the volocanoes walls. There is a tube system that carries the magma from the reservoir to the surface of the earth. Mount Rainier has a cone shape.
http://vulcan.wr.usgs.gov/Glossary/StratoVolcano/description_composite_volcano.html
