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
Geological Society of Washington Geological Society of Washington The Geological Society of Washington is a learned society based in the Washington, D.C. area. According to its constitution, "The object of the Society is the increase and diffusion of geological knowledge" The Geological Society of Washington (GSW) was founded in 1893. The core group of organizers was paleontologist C. D. Walcott and geologists S. F. Emmons and J. S. Diller of the United States Geological Survey (USGS), and artist/geologist W. H. Holmes and geologist G. P. Merrill of the Smithsonian Institution. By the end of February, 1893, they had drafted a constitution and attracted a