Evidence of the last glacial period from 10,000 years ago in Minnesota is right under your feet at Sunfish Lake Park! Glaciers develop over thousands of years as more snow accumulates than melts, and the thick layer of snow compacts over time and turns into ice hundreds of feet thick. A glacier creeps ever so slowly over a time period of thousands of years, scraping up and depositing sand and rocks along its path. The sheer density of the ice plus gravity cause a sort of ‘flow’ in the ice, deforming it and along with periods of melting, cause movement. The steep hills and slopes and ridges that are left behind are called moraines, thick layers of rocks, gravel and silt. According to a USGS map, the long hill running east to west on the southern edge of the woodland area and west of the parking lot was likely an esker, a ridge of gravel created by a river of moving water under the glacier. And how lucky for us! Because the steep slopes may have been too difficult to log, many beautiful old trees are now here for us to enjoy. Please visit the Geology Exhibit at the Sally Manzara Interpretive Nature Center for more details.