Cinder Cone Volcano

Holocene cinder cone near Veyo, Utah.

A cinder cone is a steep cone like (hense the name) volcano formed above a vent. Cinder Cone volcanoes are the most common volcano.They are steep sided cone shapes of basaltic fragments and are much smaller and much simpler than composite volcanoes.The volcano forms when ash and cinders pile up around the vent to form a circular or oval cone. Cinders are melted volcanic rock that has cooled and formed pebble-sized pieces when it is thrown out, into the air.

http://jonjosvolcanoes.weebly.com/cinder-cone-volcanoes.html