 The Antarctic sheet is divided by the Transantarctic Mountains into two unequal sections known as the East Antarctic ice sheet ( EAIS ) and the smaller West Antarctic Ice Sheet ( WAIS ) . The EAIS rests on a major land mass but the bed of the WAIS is , in places , more than 2 @,@ 500 metres below sea level . It would be seabed if the ice sheet were not there . The WAIS is classified as a marine @-@ based ice sheet , meaning that its bed lies below sea level and its edges flow into floating ice shelves . The WAIS is bounded by the Ross Ice Shelf , the Ronne Ice Shelf , and outlet glaciers that drain into the Amundsen Sea . 
