Figure 17.31

Eskers. (A) Subglacial streams flow in tunnels beneath an ice sheet, depositing sand and gravel in their channels. After the ice sheet melts, these glacial sediments create eskers. Eskers are up to 50 m (160 ft) in height. (B) This esker is located in Manitoba, Canada. For scale, note the mature trees, which stand about 10 m (33 ft).

(B. Grambo Photography/All Canada Photos/Getty Images)