SHALLOW-WATER DEPOSITS 



191 



Since o>ai>e deposits may extend far out from land where the 

 waves are strong and the water shallow, alid since the zone of shallow 

 water may he extended seaward by the aggradation of the bottom, 

 shallow- water deposits may cover extensive areas. They may 



Kif. r . io5- Diagrams showing how shallow-water deposits may attain consider- 

 able thickness by the shifting of the zone of deposition seaward. 



become deep at the same time, for as the outer border of the shallow- 

 water zone is shifted seaward by aggradation, the vertical space 

 to be filled becomes greater (compare a and 6, Fig. 195). Again, 

 if the coast is sinking, new deposits of coarse material may be made 

 on older ones. In this way, also, great thicknesses of sediment may 



be accumulated, all parts of which were deposited in shallow water. 

 The great thicknesses of some of the conglomerate beds of the past 

 show how far this may go. 



