Structure of a cinder cone <a href="https://en.wikipedia.org/wiki/volcano" class="extiw" title="en:volcano">en:volcano</a>.  Source: <a rel="nofollow" class="external free" href="https://erg.usgs.gov/isb/pubs/teachers-packets/volcanoes/poster/poster.html">http://erg.usgs.gov/isb/pubs/teachers-packets/volcanoes/poster/poster.html</a>