1878. | Physiography. 667 
reaches shoal-water, in the neighborhood 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 ques- 
tion: 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 Barbardoes in 1780, cannon which had long 
been lying sunk were washed far up on the 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 Reculver. 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 Herne Bay to the Reculvers. 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 precipitation from above ; while the clean-cut face of the cliff, 
and the sharp forms of the projecting ridges and pinnacles of the 
clay showed that since they were left in their present position, — 
they had not suffered for long the attacks of rain and wind. — 
Great cracks at the surface, here and there, showed that destruc- 
tive action was still in progress; and when I looked at the lately 
fallen blocks of earth below, I felt that it was possible that the 
grass tufts, on which I stood, might be the next to fall amidst the 
1 8vo. pp. 384, with 5 plates and 122 woodcuts (Macmillan & Co., London, 1878). : : : 
