THE WORK OF THE OCEAN. 



359 



Since spits and bars are built only where there is shore-drift in transit, 

 they are always built out from a beach or barrier. The distal end of the 



Fig. 317.— Sketch of a portion of the New Jersey coast. The dotted belt next the 

 sea is the barrier, modified by the wind. The area marked by the diagonal^lines is 

 the mainland. In the marshy area between, there are numerous channels or " thoro- 

 fares" kept open by the currents. The figures show the depths of water m feet. 

 Scale about | inch = l mile. 



