Eskers form as a result of a stream flowing on or inside
a glacier. Like ordinary streams, the stream on or in the glacier
will be transporting broken rock debris as its load. Some of this
material will accumulate along the stream on the bottom of the channel
as it is moved by saltation and traction. When the glacier melts,
this material, will be dropped onto the surface below forming a long, narrow,
winding (snake-like) ridge added to the topography.
This esker is in southeastern Wisconsin.