b'move, eventually covering about two-Glaciers andthirds of Ohio[see graphic (H)]. TheLand Forms thickest part of the glacier might havebeen about 8,000 feet thick. ThatsGeologists (people who study theabout five times taller than the Searsrock history of the earth) believe thatTower in Chicago (1,454 feet), one of theour planet has gone through several veryU.S.s tallest buildings. A glacier thiscold weather periods. They call theselarge had to weigh millions of tons (and aperiods ice ages. Ohios last ice ageton is 2,000 pounds!). When somethingseems to have ended about 12,000 yearsthis big moves, it takes a lot of materialago. During an ice age, huge glaciers arewith it, pushing the land like a giganticformed. Glaciers are large bodies of iceearthmover [see graphic (I)] .that spread over land and sometimesBecause of this earthmover,move slowly down slopes and valleys. As aOhios landforms were changed. Someglacier moves, either by spreading out orrivers and lakes were filled in with landby sliding, it also moves some of thethat moved with the glaciers. Some areasearths materials along with it. Very largewere carved out. As the glaciers moved,glaciers actually can move huge parts ofdifferent materials were picked up in thethe lands surface, flattening hills andice. Some of these materials includedforming valleys and ridges. The biggersand, gravel, soil, and minerals. Theythe glacier, the more it can change thewere moved from the northern areasland over which it moved.Ohios last glacier was like that.Geologists believe the glacier was formedin the area we now call Canada. Theglacier grew so large that it began toRemains of glacier power can be seen at the Glacial GroovesGraphic (H) State Memorial on Kelleys Island in Lake Erie. (I)page 2'