The glaciers of the North Polar regions can be divided into two groups depending on the source of their snow. The larger group is around the North Atlantic and its marginal seas; the smaller is nourished by moisture from the North Pacific Ocean. The largest ice sheet, the Greenland Inland Ice, is second in area only to the Antarctic Ice Sheet. It extends about 1,570 miles from north to south and has a maximum width of some 600 miles and an average thickness of about 5,800 feet, reaching 11,000 feet in the middle of the island. It covers an area ...(100 of 37874 words)