Mossy lava field. Mosses and lichens covering the volcanic rocks of a lava field. These rocks formed as lava (molten rock) from a volcanic eruption flowed over the area and then cooled and solidified. Initially barren, mosses and lichens are among the first plants to colonise such areas. The rocks will be weathered and broken up, eventually forming fertile volcanic soils. Photographed on the Reykjanes Peninsula, Iceland.