Igneous rock the partial melting of rocks within the mantle and crust. Extrusive igneous rocks cool and solidify quicker than intrusive igneous rocks. They are formed by the cooling of molten magma on the earth's surface. The magma, which is brought to the surface through fissures or volcanic eruptions, solidifies at a faster rate. Hence such rocks are smooth, crystalline and fine-grained. Basalt is a common extrusive igneous rock and forms lava flows, lava sheets and lava plateaus. Some kinds of basalt solidify to form long polygonal columns. The Giant's Causeway in Antrim, Northern Ireland is an example. The molten rock, with
Jesse S. Cave Jesse S. Cave Jesse S. Cave (1872–1948) was briefly acting mayor of New Orleans from July 15 to August 17, 1936. Cave arrived in New Orleans in 1904 as a manager of an iron cistern company, and was elected president of the New Orleans Board of Trade in 1930. In 1932 he was elected Louisiana State Treasurer. Along with A. Miles Pratt and Fred A. Earhart, Cave was one of three acting mayors who served in the summer of 1936 between the resignation of Mayor T. Semmes Walmsley and the accession of Robert Maestri. After his brief tenure as acting