The Johnstown moraine is made up of three different materials. The lower part of the sequence consists of closely spaced bodies of boulder gravel, which are cylindrical and plunge upglacier several degrees. They are interpreted to be esker bodies. They grade distally into proglacial outwash fans. The esker bodies are overlain by sandy till, some of which is uniform and some of which has colour layers. The colour layers are a few millimetres to a metre thick, drape over the eskers and dip upglacier several degrees. Both the uniform and layered till have pebbles plunging upglacier several degrees steeper than the dip of the layers. Both the uniform and layered till are interpreted to have been deposited subglacially, probably both by melting out and by lodgement. The till is overlain by a thin layer of boulder gravel interpreted to be washed supraglacial sediment. ?? 1993.
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Deposition of the late Wisconsin Johnstown moraine, south-central Wisconsin