SEA-BENCHES 1 3 



be sure that the position of the coast has been recently 

 changed, that the land has been either lowered or uplifted. 



It is a feature deserving attention that these wave-benches 

 rarely retain on their surfaces any considerable part of the 

 debris which has been removed from the cliffs : here and 

 there, scattered over their surfaces, we find bits which have 

 been fastened in the crevices of the bench, but except where 

 fresh fragments are supplied by the fall of the masses of rock, 

 the wide surface is usually as clean as a floor. This feature 

 is peculiarly well shown on the great Yorkshire wave-terrace, 

 but is noticeable in all similar structures. It is, in a word, 

 evident that all the matter torn from the receding clift"s is 

 in some w-ay removed to a distance from the place where 

 it falls ; a little consideration and a few observations on the 

 ground will show us the manner and the measure of its re- 

 moval. Let us first notice that nearly all the detritus at the 

 foot of the cliffs is of a pebbly nature ; in general it consists 

 of quite large stones wdiich have been very much rounded. 

 It is evident that a large part of the rock which has been 

 worn from those stones w^as taken away in the form of powder 

 or sand. We can often, in the case of granite pebbles, see 

 that the surfaces have been crushed by the blows they have 

 received. We readily apprehend the fact that in the mill of 

 the surf at the base of these rocky precipices, the fate of the 

 rocks is to be ground into a very fine grist, which is easily 

 borne away to a distance by the strong currents which exist 

 in times of storm. 



If the waves rolled directly in at right angles to the face 

 of the cliffs, and the wind blew in the same direction, the onh- 

 current which would exist on the shore would arise from the 

 reflex of the water and the undertow or current which sets 



