6004813 The grinding away of rocks by slowly moving glaciers form deep valleys, thus contributing to the constant changing of the earth\'s face (litho) by English School, (20th century); Private Collection; (add.info.: The grinding away of rocks by slowly moving glaciers form deep valleys, thus contributing to the constant changing of the earth\'s face. Illustration for General Knowledge Course (Odhams, c 1945).); by Look and Learn; English, out of copyright.