THE CHANGING FACE OF NATURE 13 



Chicago Drainage Canal, conveniently reached at Willow Springs, 

 or on the rock dumps of the coal mines near Braiderwood, on the 

 Chicago & Alton Railroad. 



Wind must be regarded as an agent of land destruction, and 

 a transformer of the landscape. One needs only spend a day in 

 the Dunes to realize its efficiency, if that day be a windy one. 

 There is visible evidence that the wind is moving the sand; the 



FIG. 13. A moving 

 on its margin. 



dune invading a swamp and burying pines and junipers 



air is full of it. Close to the ground it is drifting along and 

 strikes one's hand or face, when lying down, with stinging force. 

 The hills of sand are moving inland (Fig. 13) covering up the 

 forests, invading the streams, and turning them from their 

 courses. The movement of the great dunes, hills of sand 

 hundreds of feet high and thousands of feet long that sweep 

 along like snow drifts, is quite rapid. The steep front may 

 advance several feet a year, by actual measurement from stakes 



