AGENTS AT WORK IN THE OCEAN 297 
By the undertow,’ fragments are dragged out to sea 
along the bottom. Worn upon the beaches, the finer 
fragments in part pass outward, lodging finally on 
the sea bottom at a distance from the coast, where 
the force of the undertow current has so diminished 
that further transportation is impossible. 
The blowing of the wind starts a slowly moving 
surface current, in 
which fragments may 
also be carried. Also, 
as waves strike the 
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coast, reaching _ it 
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diagonally, a shore bee ON 
current is produced | See 
in connection with = 
Fie. 126. 
the change from the A part of the coast of New England, showing 
wave proper to the bars built by waves and shore currents 
: ‘ moving in the direction of the arrows. 
breaker, which is a 
bodily forward movement of the water. In this way, 
fragments, often of considerable size, are driven along 
the shore (Fig. 126). So the waves have allies (includ- 
ing the tides), which serve to clear away the materials 
that they have prepared for removal, and thus leave 
the shore open to their further attack. 
1 The action of the undertow is often illustrated disastrously when bathers 
are caught by it, dragged to the bottom and carried out, being held under 
until life is extinct. 
