The landform of the Prairie ecozone is very unique. The topography of the ecozone is flat in some areas, to rolling in other areas. Glaciation has helped form the shape of this area. Glaciers has helped flattened the land. Underneath the ground, they have many layers of sedimentary bedrock. There are oil and gas found trapped in isolated pockets and cracks. Glaciers have left flat fertile land in southern Manitoba and that has resulted in heavy clay soils that lay beneath lakes. The major rivers in the area originated from the Rocky Mountains. These rivers flow east all across the ecozone. The rivers have variable water flow rates and sometimes, because of the high evaporation rate, they become dry for long periods of time. The Prairie ecozone has a great variety of surface landforms.