Igneous rock the partial melting of rocks within the mantle and crust. Extrusive igneous rocks cool and solidify quicker than intrusive igneous rocks. They are formed by the cooling of molten magma on the earth's surface. The magma, which is brought to the surface through fissures or volcanic eruptions, solidifies at a faster rate. Hence such rocks are smooth, crystalline and fine-grained. Basalt is a common extrusive igneous rock and forms lava flows, lava sheets and lava plateaus. Some kinds of basalt solidify to form long polygonal columns. The Giant's Causeway in Antrim, Northern Ireland is an example. The molten rock, with
Cave of the Angel Cave of the Angel The Cave of the Angel refers to several cave-related structures placed at Aras mountain range at the town of Lucena, Córdoba province in Spain. Here, it is located an Acheulean site that spans from the Middle Pleistocene to the Upper Pleistocene. There are geological, paleontological and archaeological evidences indicating an intense and long term occupation of this site. The study of numerous bone and lithic remains found in this site reveal exposure to fire. This along with the finding of a wide and deep combustion structure in the stratigraphic profile support the hypothesis that at the