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
Cave S it was covered in a soil that had the consistency of snuff in 1910. Despite not finding any bats he thought that the snuff-like material was vegetable matter and bat guano. Various human artifacts such as pottery, stone implements and other stone objects, a shell armlet, perforated cyprcea, charcoal, burnt bone and broken shellfish and a wide variety of bird remains and mammalian fauna have been found in the cave. The human bones were thought to come from one male skull-less skeleton which appeared to have notably thick bones. Cave S Cave S is a limestone cave in the British