CHAPTER II 



THE BEACH AND ROCKS 



BoTANiCALLY speaking the sandy Beach between 

 the tide-marks is an uninteresting thing, for it is 

 desert. You may walk for miles along it, and find 

 below the high-tide mark no sign of active vegetation. 

 Seaweeds may be littered here and there, but they 

 will be in varying stages of decay. You take up 

 a handful of sand and examine it : it will be chiefly 

 composed of grains of silica, but with many fragments 

 of shells of animals, and occasionally of the lime- 

 incrusted remains of certain coralline seaweeds. But 

 the conspicuous fact is that active vegetable life is 

 absent from the moving sand. The reason for this 

 is not far to seek. It is that, apart from the floating 

 life of the open waters, or Plankton, as it is called, 

 seaweeds with few exceptions require a fixed sub- 

 stratum. How diflerent from the barrenness of 

 the loose, disintegrated, and ever shifting sand is 

 the condition of any rock or wooden pile Avhich 

 you may see exposed between the tidal limits, or 



