Hirsikangas ancient shore banks

After withdrawal of the ice, Rokua Geopark was initially covered by the Lake Ancylus. The ice sheet had depressed the earth's crust, so as the ice melted, the land began to lift up. The highest terrain points in Manamansalo and Rokuanvaara Hill were elevated above the water level in a couple of hundred years. Waves and wind deposited esker sand into beach ridges parallel to the shoreline. In the Hirskikangas area in Muhos, the kilometres-long ridges were formed on the coast of the Litorina Sea about 7,600 years ago. In many places there are mires between the beach ridges.