SETTLEMENT AND BOND. 



281 



eroded material being withdrawn by the play of the waves into 

 the open joints. The danger of such cavities in work has already 

 been frequently referred to. 



In some cases the face-blocks of battered work have been 

 secured in the manner indicated by Fig. 92. This system is 



Fiu. 93- [SECTION] 



FIG. 95. [PLAN] 



FIG 94. [PLAN] 







suitable for the stepped facing of blocks sometimes used for 

 protecting the slopes of rubble mounds, but its success depends 

 to a very great extent upon the care with which the bottom 

 blocks are laid and secured. 



