MICHIGAN'S SHIFTING SANDS. 



29 



Fig. 10. 

 of a trail. 



A break in the surface of an established Md wooded 'I'""'.' 1 ":' 

 This started the sand to (ravelin* through the timber until it 



o 



o a tra. s starte e san o raven 



and buried a foot bridge. A bad traveling dune was soon 1 



'' ' rivine 



