Hornito

A hornito is a conical or pipe-like structure built up by lava spattering or being ejected through an opening in the crust of a lava flow. Hornitos resemble spatter cones but are rootless, meaning they were once sources of lava without being directly connected to a true vent or magma source; they usually form through the slow upwelling of fluid lava through the roof of a lava tube, often associated with pahoehoe lava of basaltic composition, and can exceed ten meters in height.