SAND DUNES AND SALT MARSHES 



their composition, but at Ipswich the color 

 of the dry sand is brilliant gray or white, 

 although it may appear purple in the shadows 

 or pink or gold in the sunset light. The winds 

 have a selective power, and streaks and wind- 

 rows of purple and garnet or even of black 

 sands are often to be found. Under the micro- 

 scope the grains appear like gems, and are 

 seen to be more or less rounded and worn by 

 the constant action to which they are sub- 

 jected by the wind, while on the beach the 

 majority of the grains are still somewhat an- 

 gular, as if recently broken up by the pound- 

 ing waves. The difference is not great, but 

 is generally discernible. In size the sand 

 granules of the dunes are smaller as a rule 

 than those of the beach. 



In the early spring the cranberry bogs large 

 and small among the dunes are generally 

 pools of water, and here, where vegetation 

 abounds, the water is stained a brown color. 

 Occasionally a pool may be found free from 

 vegetation higher up in the sand, and the 

 water appears in its true color, a greenish 

 blue, suggestive of an alpine lake, and the 

 snow-white peaks of sand in the vicinity serve 

 to increase the illusion. 



24 



