A long, narrow, sinuous ridge created by deposits from a stream running beneath a glacier.
2001, Allan D. Randall, Hydrogeologic Framework of Stratified-drift Aquifers in the Glaciated Northeastern United States, US Geological Survey Paper 1415-B, page B37,
The multiple deltas must have formed sequentially, which led Thompson (1982) to conclude that the eskers were built in successive segments.