Giant's Causeway cases the horizontal fracture has resulted in a bottom face that is convex while the upper face of the lower segment is concave, producing what are called "ball and socket" joints. The size of the columns is primarily determined by the speed at which lava from a volcanic eruption cools. The extensive fracture network produced the distinctive columns seen today. The basalts were originally part of a great volcanic plateau called the Thulean Plateau which formed during the Paleocene. According to legend, the columns are the remains of a causeway built by a giant. The story goes that the Irish
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