Cauliflower A’a Lava

Very commonly, lava tubes are floored with a rough, bumpy, frothy surface that is transitional between smooth, ropy pahoehoe lava (common on tube floors) and pure a`a lava (which is unusual on tube floors).  It may include chunks of breakdown and broken pieces of stalactites.  The cauliflower form is a solid floor, whereas floors with loose fragments of rough lava (as opposed to breakdown) are called clinker floors.