IN THE SEA 175 



Now watch this. The retardation of each wave 

 having been the same, it follows that the time 

 interval between them will remain as it was, and 

 we have only to take out our watch and time them 

 to know what waves these were when they raced 

 (more or less) mountains high in mid-Atlantic. 

 Thus. Twelve seconds between waves ; squared 

 is 144 ; multiplied by 5, and we have waves 

 measuring 738 feet from crest to crest. (Where- 

 upon we fall into a mid-day sleep in which all the 

 glad sounds and sensations of an August day by 

 the sea are like things seen through tissue paper.) 



Everything that we see on the seashore is strange 

 and new to the dweller in the back country. The 

 plainest link between the life of the sea and of the 

 dry land is the snail, and the snails of the sea 

 constitute fully nine-tenths of all the animate 

 forms we shall find. Going down the cliff path we 

 see lots of land snails, in fact, most of them seem 

 to be more common at the edge of the sea than in 

 the lanes at home. But when we get to the beach 

 we find such a wealth of species and so many forms 

 not even faintly represented on shore that the 

 most casual observer must find that the sea is the 

 headquarters of the great molluscan order. 



The first band of the shore below high-water 

 mark is occupied with great uniformity by a genus 

 of stomach-foots or gasteropods called Littorina. 

 The common periwinkle is the best-known type, 

 but before we get to the rocks occupied by the winkle 



