598 



RELATION TO ENVIRONMENT. 



some left standing and others fallen, are sometimes spoken of 

 as " forest graveyards" in the track of the dune. These are 

 often found in the track of wandering dunes on the eastern 

 shore of Lake Michigan and also on the Atlantic and Gulf coasts. 

 Wandering dunes often encroach upon cultivated fields which are 

 near the coast line, and thus may bury valuable arable land. 



1091. Rejuvenated dunes. As stated above under the head of 

 kinds of dunes, a rejuvenated dune is one which has become 

 old and inactive for a period, but becomes active again for one 

 or more reasons, some of which have been mentioned above. 

 Some very interesting cases of rejuvenated fossil dunes are 

 known in New York not far from Lake Ontario. 



The shore line of the great lake in glacial times which occu- 

 pied the present site of Lake Ontario is still evident as a promi- 



Fig. 523. 



Planting grasses on wind-swept sandy coasts to prevent movement of dunes 

 into the city, Southport, England. (Photograph by the author.) 



nent ridge some fifteen to twenty miles south of the present 

 shore. In some places in Oswego Co., N. Y., according to 

 Professor Rowlee, are sandy elevations which were formed by 

 dunes on the shore of this glacial lake. After the waters receded 



