Iceland is, generally speaking, a mountainous country. Many of the mountains are also volcanoes, or once were, and many, also have glaciers, or are buried in glaciers. Most of its highest mountains are in the south/southeast, where Hvannadalshnukur, Iceland's highest, is located. Most of its rock is basalt, with other volcanic rocks such as rhyolite and andesite making up the rest. There are tiny amounts of sedimentary rocks, including even sparse fossils, in thin layers between lava and ash layers. The coastal mountains are strongly carved by glaciers into narrow, deep fjords.