Ice age
The farmland consists mostly of clayey soils because for many thousand years the ocean covered what now is Gilberga parish. The Ice Age affected the area, the ground was elevated from the ocean level and clay was left in this place as the ocean withdrew. An interesting finding from the Ice age are the big sand hill in Nysäter and Hasslerud. By the shore of the Gillberga lake, the water has been swirled the sand and done so that the rocks are round cut.