CHAPTER II 

 The Sea Shore 



That narrow strip between the high and low-water marks 

 of spring tides which we call the sea shore is the haunt of a 

 rich and varied collection of plants and animals and has, 

 on account of its unique position at the junction of sea and 

 land, an interest altogether out of proportion to its area. 

 Many books have been written about the sea shore and its 

 inhabitants, for the subject is a big one and teeming with 

 interest, but in this volume with its wider scope we can only 

 devote one chapter to it and endeavour to give some general 

 idea cf the many fascinating problems it presents. Those 

 who are sufficiently interested are advised to seek furthel 

 information in the books recommended at the end of this 

 volume. 



The extent of shore uncovered at low tide naturally 

 depends on the sharpness of slope, and this depends on a 

 variety of factors, the nature of the land, its configuration 

 and the action of the tides, currents and rivers, being the 

 most important. Anyone who has lived near the sea knows 

 how in some places the outgoing tide uncovers great areas 

 ot mud or sand, while in others, with a quickly descending 

 shingle beach, only a comparatively small area is uncovered 

 at the lowest spring tides. It has been estimated that the 

 total area between tide marks in Great Britain and Ireland 

 amounts to some 620,000 acres. We can distinguish 

 between three types of shore, formed of rock, sand or mud, 

 though these may be mixed to a greater or less extent. 



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