Giant's Causeway with higher saline content than that found at the causeway. Although the basaltic columns of the Giant's Causeway are impressive, they are not unique. Basalt columns are a common volcanic feature, and they occur on many scales (because faster cooling produces smaller columns). The Belfast-Derry railway line run by Northern Ireland Railways connects to Coleraine and along the Coleraine-Portrush branch line to Portrush. Local Ulsterbus provide connections to the railway stations. There is a scenic walk of 7 miles from Portrush alongside Dunluce Castle and the Giant's Causeway and Bushmills Railway. Giant's Causeway The Giant's Causeway is an area of
Cave-in-Rock State Park the meltoff following the Wisconsin ice age. It was not formed by typical karst processes like Mammoth Cave in nearby Kentucky; it is a tunnel eroded into the bluff. Cave-in-Rock was known and used for thousands of years by the Native Americans. The first European to discover the Cave was M. de Lery of France, who in 1729 mapped and named it ""caverne dans Le Roc"" (cf. supra). This name, translated directly into English, is the name the cave bears to this day. Other names for the cave included Rock-In-Cave, Rocking Cave, Rock-and-Cave, House of Nature, The Cave, Big Cave,