A cone of lava
fragments built on the surface of a lava flow
pouring into a body of water, usually the sea, is called a littoral cone
("littoral" refers to a shoreline). Lava
entering the ocean heats and boils seawater, often generating steam explosions that hurl tephra
onto the shore, including spatter, bombs, blocks, ash
,, lapilli, and, rarely, limu. As the various tephra accumulates on the shoreline, a well-developed cone may be created.