A typical size is one kilometer long, 20 meters high, and 500 meters wide.  
Their name is derived from the Gaelic for "rounded hill" or "mound."  A typical size is one kilometer long, 20 meters high, and 500 meters wide.  Commonly found clustered, they disrupt drainage such that lakes and swamps may be formed.  For 10 points, name these oval or elongated hills formed by the movement of glaciers across rock debris, or till.
Their name is derived from the Gaelic for "rounded hill" or "mound."  
drumlins