Drumlin Hill (IMAGE) University of Toronto Caption Shaped like an upturned boat, drumlin hills (pictured above) are found clustered together in their hundreds and thousands in distinct fields called swarms. They're the most common landform across large areas of northern North America and Europe, marking the footprint of massive ice sheets that formed during past ice ages. Credit University of Toronto Scarborough Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.