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 S sea level and below the Great Gibraltar Sand Dune that was once used to capture rainwater which served as Gibraltar's main water supply. The cave is about from the north end of the Rock and opens on the east face of the Rock just above Holy Boy's Cave. The cave provides evidence of marine life indicating that despite its current altitude it was once a sea cave. This is not the only evidence of rising and falling sea levels in Gibraltar which have historically varied greatly. Wynfrid Duckworth described the cave's floor as falling in height towards the entrance and