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
Bodorna Rock Columns Natural Monument some resemblance with figure of the Christian monk. Monument origin is not completely clear, as it may be a denudational relict from a neogene conglomerate or from naturally cemented cobbles known as pinnacle or hoodoo that was later altered by man for cult purposes. Detailed lithostratigraphy studies are not available. At the base the rock column has diameter of 4 m and column gradually narrows towards the top. Presently the column surface is covered with shrubbery. The column contains a small cave with two niches, one of many, that were utilized as a shelter by early Christian monks in Georgia,