Lava flows near the coast tend to spread out laterally and enter the ocean over a large front. Several lava tubes may be active across the flow front. Larger lava tubes feed down slope and maintain pressure in the growing lobes that extend into the water. Flow lobes develop most readily on steep slopes and result in stacks of pillow "tongues" that parallel the offshore slope. This offshore stack of lava produces beds of rubble parallel to the offshore slope. Geologists call these steeply dipping beds foreset beds.