In the 1830s Louis Agassiz proved that these moved, bringing with them the rocks & boulders that covered Europe
[DOC] [TLE] Strange-Looking Tombstone Tells Of Moving Ice, Ancient Climates ... [PAR] Dec 5, 2012 ... A rough, clumpy hunk of granite, carried across Europe on a sea of ice, ... Louis 
Agassiz was one of the first scientists to make sense of rocks like these.