When the glaciers receded from the area that is now Wisconsin about 10,000 years ago, they had sculpted a unique landscape known as a kame field along a section of the Kettle Moraine near current day Hartford. As the glacier melted, streams formed that deposited sediments in a triangular shape. The action of the stream flow sorted the different sediments, resulting in stratified layers of silt, sand and gravel. This action created a series of steep triangular hills known as delta kames, combined with "kettle" lakes in this area. Many kames have been mined for their valuable sand and gravel, but a spectacular one is protected in what is now the Pike Lake Unit of the Kettle Moraine State Forest.