A photograph taken from the cliff near the delta of ancient block and ash flow deposits. Most of the Island consists of these type of deposits which are Andesitic to Dacitic in compisition. You can see that some of the blocks, such as the one Matt is casually leaning on (note the sunburn to correct your screen colour), can get very large. The black sand beaches are a result of the rare lava flow events which occur as the final stages of erruption activity when the magma chamber is activated and the lower more mafic material is ejected.