NE-SAW-JE-WON 



In the early-inhabited parts of the glaciated district they were 

 used for burial places, as generally the soil cover was thin and 

 their gravel content provided good drainage. In many places 

 they furnish gravel and sand for road building and other con- 

 struction. Long narrow hills that look like abandoned rail- 

 way embankments mark the sites of walled or tunnelled chan- 

 nels of streams which flowed upon, within, or under the ice. 

 These stream channels became choked with rock debris, and 

 when the ice melted the water-sorted material settled to the 

 land surface, its sides assuming characteristic steep angles of 

 repose. These sinuous hogback ridges, known as eskers, may 

 be from a few feet to more than a hundred feet high and 

 from a fraction of a mile to many miles long. They are on 

 the till plains and in the moraines. 



Other strange products of glacial building are drumlins, 

 curious hills shaped like inverted canoes, found on the till 

 plains, aligned in the direction of the ice movement. Some 

 drumlins, such as those on the limestone Cheneaux Islands, 

 and the lenticular hills in the drumlin area of Grand Traverse, 

 Michigan (found on excavation to have cores of shale covered 

 with a plastering of pebble-set clay), evidently were "shaped 

 into drumlinoid form by the ice passing over them"; some are 

 sculptured till; and others are a special form of ground mor- 

 aine — mounds of glacial till with elliptical bases. Drumlins 

 may be from fifty to three hundred feet high and from one- 

 fourth mile to one and one-half miles long; many of them are 

 steepest on the end facing the direction from which the ice 

 came. The exact manner of origin of these remarkable hills is a 

 matter of much speculation. They are usually arranged in 

 fan-shaped groups; and it is believed that in some way they 

 were carved from old till by readvance of local ice lobes, or 

 were accretions of till beneath the ice along margins of broad 

 lobes — perhaps in long crevasses, or are hills carved in the 

 bed-rock by the advancing glacier and coated over with stony 

 clay left by melting ice. Excellent examples of drumlins may 



26 



