SAND DUNES 559 



since been buried by the advancing dunes. (Forchhammer-i6:^7.) 

 A similar case is shown in the changes produced by migrating dunes 

 on the Kurische Nehrung. in East Prussia, where a church was 

 buried and again resurrected by the advancing dunes between the 

 years 1809 and 1869. 



On the south coast of the Baltic exists another important dune 

 area of Europe, its strongest expression being found on the Ku- 

 rische and Frische Nehrung. two very long narrow sandbars sep- 

 arating off shallow lagoons on the coast of East Prussia. The 

 height of the dunes here reaches 60 meters and more, and hence 

 these are. next to those of the Gascony coast, the most important 

 coastal dunes of Europe. 



Dunes of great size and covering an extended area occur on 

 the North African coast of the Mediterranean, especially on the 

 Great Syrt. Elsewhere on the Mediterranean coast they are of little 

 importance. 



The dunes of the east coast of North America have been studied 

 to a much less extent than those of the European coast. Perhaps 

 the best-known region is that of the extreme tip of Cape Cod at 

 Provincetown, where the dunes reach a height not exceeding 30 or 

 40 meters. This entire section is a region of sandbars and beaches 

 built by the waves and shore currents from material washed from 

 the Truro and Wellfleet coast, a region exposing high cliff's of gla- 

 cial and earlier sands to the open Atlantic. The dunes built at 

 Provincetown slowly advance southward and westward, burying 

 forests and hamlets in their path, though their march has to some 

 extent been arrested in the Provincetown region by artificial means, 

 at an expenditure of $28,000 between the years 1826 and 1838. 



On the Long Island coast the dunes are moderate, but on the 

 New Jersey coast and on that of the Carolinas they reach a consid- 

 erable height and extent, and in their inland march bury forests 

 and even buildings. 



(2) Lake Shore Dunes. These are well illustrated by the dunes 

 so extensively developed on the eastern shore of Lake Michigan 

 from the Straits of Mackinac to the Chicago area. Here extensive 

 glacial sands in part forming beach lines of a subsequent lake stage 

 of greater extent than the present are heaped into sand dunes by 

 the prevailing westerly winds. Some of these sand dunes on the 

 northwest coast of Michigan are grassed over and wooded, but 

 others are still in an active state of movement, advancing upon and 

 burying the forests. In height these dunes range to a hundred feet 

 or more, especially in the southern area, as in Dune Park, In- 

 diana. Near Muskegon, Michigan, occurs one of the largest dunes 



