As the glacier became more rock and less ice, there were some bizarre landforms, like these giant ice hills. Just under the sand is ice. Where the sand is, ice melts more slowly, where the sand isn't, ice melts more quickly, As it melts, lower areas become the channels for small streams which carry sand away and melt more ice. So the result is a landscape of dozens of giant hills of ice capped with sand. We slept on one for the night.