Geology of Ireland longest known free-hanging stalactites. Geology of Ireland The geology of Ireland consists of the study of the rock formations in Ireland. The island contains rocks from every age from Proterozoic to Holocene and a large variety of different rock types is represented. The basalt columns of the Giant's Causeway together with geologically significant sections of the adjacent coast have been declared a World Heritage Site. The geological detail follows the major events in Ireland's past based on the geological timescale. The oldest known Irish rock is about 1.7 billion years old and is found on Inishtrahull Island off the north
Prometheus Cave Natural Monument Prometheus Cave Natural Monument Prometheus Cave Natural Monument () also known as "Kumistavi Cave" () and "Tsqaltubo Cave" () is a karst cave located in Tsqaltubo Municipality in Imereti region of Georgia. The total length of the cave is about 11 km, of which 1060 m are open to visitors. Cave has total of 22 halls of which six are currently open to tourists. The cave was discovered and studied by Georgian speleologists in the early 80's of the 20th century. It is part of a large cave system, united by one underground river. Currently, about 30 km of the