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 are convenient sources for sand and gravel. Thus, many have been destroyed by quarrying operations. Fortunately, this one northwest of Fordville, N.D., has been conserved.