=>0 SEA AND LAND 



which flourish in arenaceous soils, and in the close-set leaves 

 and stems, and are protected from the currents of air. 

 Where the movement of sand is most rapid, it may bury 

 these plants out of si^ht, but most of them are tolerant of 

 this submersion and cjuickly grow upward and make a new 

 entanglement for the nioving grains. In this manner the 

 crest of the beach grows upward in an irregular manner, 

 its crown bearing a range of hummocky sand-hills which 

 often rise fifty feet or more above their base, and in 

 favorable situations may attain a height of two hundred 

 feet. 



The dunes, as they are termed, are less abundant on the 

 l^eaches of the Atlantic coast than in many other parts of 

 the seaboard, for the reason that the prevailing winds of that 

 region are froni the west ; and the sand swept up from the 

 sea-marein is, to a crreat extent, carried back h\ the off-shore 

 winds ; even the scanty dunes of our shore w^ould hardly 

 exist were it not for the fact that the vegetation on the land 

 side of the elevations is generally quite luxuriant and holds 

 the sand which has been brought to its protection from the 

 shore. The most characteristic dunes of our sea-coast are 

 found where there is a stretch of shore which, by some irregu- 

 larity of the coast, is exposed to the sweep of the western 

 winds. Thus the seaward extremity of Cape Cod is largely 

 made up of windd^lown sands. So, too, the long stretch of 

 shore tending to the southeastward from Portsmouth, N. H., 

 to the mouth of the Annisquam tidal river in Massachusetts, 

 yields to the northwest winds a good deal of sand, which 

 is carried down to the great dunes of the Essex district on 

 the mainland. "The Banks" of North Carolina, fifteen to 

 twenty-five miles distant from the mainland enclosing the 



