NORTH DAKOTA STATE UNIVERSITY - FARGO, N D
An esker is a sinuous ridge of stratified sand and gravel that was formed by a meltwater stream flowing underneath stagnant glacier ice. The stream flows through a tunnel within the ice, depositing sand and gravel (outwash) on its bed. Later, when the ice walls melt away, the bed is left as a winding ridge on a landscape. Because they are both landforms resulting from stagnating ice, eskers and kames often occur on the same landscape.
Eskers abound in the stagnant ice terrain around Tower City, ND. Some are striking --- and others subtle, such as this low esker about 2 miles west of Tower City.