Earth and rock worn and smoothed by ice sheets, along with U-shaped [[valley]]s and termination deposition debris, are the main evidences for an Ice Age, and there is evidence of such [[glacier|glaciation]] covering northern [[Europe]] (including most of [[Britain]]), most of [[Canada]], and into the northern parts of eastern half of the [[United States]].<ref Name="WBE">Ice Age, World Book Encyclopedia 2000 CD ROM</ref> | Earth and rock worn and smoothed by ice sheets, along with U-shaped [[valley]]s and termination deposition debris, are the main evidences for an Ice Age, and there is evidence of such [[glacier|glaciation]] covering northern [[Europe]] (including most of [[Britain]]), most of [[Canada]], and into the northern parts of eastern half of the [[United States]].<ref Name="WBE">Ice Age, World Book Encyclopedia 2000 CD ROM</ref> |