of volcanoes in its area. Before its formation the Crary Mountains might have been islands. In the Crary Mountains, ice occurred either in the form of slope ice when the mountains were erupting or as a thick continental ice sheet. The glaciers were cold-based and thus did not produce tillites or glacial surfaces, and were probably thin. Glacial erosion took place mainly between 8.55 and 4.17 million years ago; it formed the cirques in Mount Rees and Mount Steere and transported glacial erratics on the mountains. See also Runyon Rock References Sources External links Crary Mountains Volcanoes of Marie Byrd Land Miocene shield volcanoes Pliocene shield volcanoes Pleistocene shield volcanoes