242 C. Lloyd Morgan — Physiography. 



storm-cloud bangs over the distant horizon, at our feet is a little 

 streamlet running over the sands to the sea; behind us is the 

 white chalk cliff, capped with sand and clay. 



How come these waves, and what are they doing? shall be 

 our first question. The answer to the first part of the question is 

 so obvious that a child will not hesitate to reply, that it is the 

 wind which produces the waves. At first a mere cat's paw on 

 the surface of the sea, the growing ripples are, as the wind continues, 

 hurried onwards, increasing both in length and breadth, and, where 

 the water is deep, in velocity of motion, until they become the great 

 waves, some 14 feet high from trough to crest, which we see on 

 our coasts during a storm, and finally, if they have a fair field, 

 develope into ocean bUlows, 26 feet high in the Atlantic, 40 feet 

 high in the Southern Ocean. In the open sea the water is not 

 carried forward by this wave motion. We may watch the sea-bird 

 rise and fall as the wave passes under her. Slie is not carried 

 forward on its summit. But when the wave reaches shoal-water, in 

 the neighbourhood of land, the lower part is retarded by friction 

 against the bottom, while the upper part hurries on, and the wave 

 breaks, and rushes up the shore, the under water racing back and 

 tearing up the beach in its backward course. It is in this way 

 that the sea has such power in grinding down the rocky materials 

 which fall to the base of our island cliffs. Along the Chesil Beach 

 the pebbles are carried forward fifteen miles by the action of the 

 waves, and as they grind over each other in their westward course, 

 they become smaller and smaller. 



Here then we obtain an answer to the second part of our question : 

 What are the waves doing ? They are beating backwards and 

 forwards the matter which falls from the cliffs, until it is broken 

 up and rolled into a rounded pebbly beach. But they are doing 

 more than this. They are battering at the cliff itself, and, aided by 

 rain, and frost, and wind, are eating away our island shores. The 

 force with which the waves dash against the cliffs is at times 

 enormous, having been known to reach a pressure of more than 

 three tons on the square foot. During the hurricane which swept 

 over Barbadoes in 1780, cannon which had long been lying sunk 

 were washed far up on shore. 



In some parts of England the sea is advancing rapidly on the 

 land. Prof. Huxley, in his excellent little book on Physiography,' 

 quotes, as an instance, the fact that Eeculver church, which in the 

 time of Henry VIII. was a mile from the sea, is now only preserved 

 from the destructive action of the waves by a stone breakwater 

 made by the Trinity Board. Not long ago, I walked along the 

 coast from Heme Bay to the Eeculvers. The rapidity of the waste 

 was clear. In many places portions of the path had been carried 

 away, Masses of grass-covered earth, lying at the foot of the 

 vertical portion of the cliff, showed how recent had been the pre- 

 cipitation from above ; while the clean-cut face of the cliff, and the 

 sharp forms of the projecting ridges and pinnacles of the clay, 

 1 8yo. pp. 384, with 5 plates and 122 woodcuts (Macmillan & Co., London, 1878). 



