GLACIERS 



229 



FIG. 249. Bridgewater Esker, Rice County, Minn. (R. T. Chamberlin.) 



they flowed. On the melting of the ice these deposits re- 

 mained as serpentine ridges, called eskers (Fig. 249). Like 

 the material of kames, that of eskers is usually rounded and 

 poorly stratified (Fig. 250). 



The bulk of the stratified material of the ancient drift 

 sheets does not form distinct topographic features, but is 

 scattered in irregular belts and layers within and beneath 

 the till, as well as upon it. 



FIG. 250. Section of an esker near Randolph, Wis., showing its com- 

 position and structure. Many eskers are composed of much coarser ma- 

 terial. (Miller.) 



B. & B. GEOL. 13 



