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
Cueva del Milodón Natural Monument Cueva del Milodón Natural Monument Cueva del Milodón Natural Monument is a Natural Monument located in the Chilean Patagonia, northwest of Puerto Natales and north of Punta Arenas. The monument is situated along the flanks of Cerro Benitez. It comprises several caves and a rock formation called "Silla del Diablo" (Devil's Chair). The monument includes a cave which is notable for the discovery in 1895 of skin, bones and other parts of a giant ground sloth called "Mylodon darwini". The largest cave in the monument is the long Milodón Cave. It was discovered in 1895 by Hermann Eberhard, German explorer