OF MABINE COASTS. 01 



THE NORTH SEA. 



The West Coast of Denmark, 



from Cap Skagen, the northernmost point of Jutland, is sandy along 

 its whole length, and the sandy shore continues through Schleswig- 

 Holstein to the mouth of Elbe river. (See Fig. 5.) This dune district 

 comprises an area of some 70,000 hectares. The dunes do not run to 

 any considerable height, 32 m. being given as the greatest. A chain of 

 islands follows the southern part of this coast and they are all sandy. 

 On the island of Sylt, the height of the steep coast is 34 m., and on this 

 dunes up to 28 m. in height are developed. 



The size of the grains on these dunes along the Forth Sea coast 

 decreases southwards from Skagen. On Anholt, Jessen still found, 

 however, a dune sand in which 91% of the grains had a diameter of 

 over 2 mm. Jentzsch, in Gerhard's handbook, mentions that samples 

 of dune sand from Sylt contained grains of the largest size; while the 

 finest sand came from Borkum. On the small island Norderney, out- 

 side the German North S'ea coast, the sand grains are of very small size, 

 0.11 mm. in diameter according to Wessely. 



The Danish and German North Sea dune flora is the best known, 

 many investigators having worked here, principally Warming and 

 ReinJce. The writer's personal knowledge of the dunes on Jutland is 

 confined to a few points, visited in 1900. 



SAND DUNES IN HOLLAND. 



The belt of sand dunes which, as already mentioned, marks the 

 coast from north of Jutland to Elbe, continues from that river almost 

 without any break along the southern shore of the North Sea to the 

 Straits of Calais, for a distance of about 500 km. In most other coun- 

 tries the dunes are a source of trouble through injury to forests and 

 cultivated fields, but in Friesland, Holland, and Belgium, they are a 

 protection against the invasion of the sea, being natural dykes. Their 

 height is not very remarkable and they very seldom reach over 20 m. 



The dunes are especially well developed on the West-Friesian islands 

 and on the mainland between Heider and Hoek van Holland. This 

 dune belt is mostly of a comparatively narrow width, but in some places 

 as in the neighborhood of Haag it covers several kilometers inland from 

 the sea. 



