9 original; 10 counterpart; the latter placed so that the rill dis- 

 charge is toward the bottom of the page. One may note here as on 

 the preceding figures the flanges at the side of the rilled channels 

 which indicate a stronger followed by a weaker flow of w r ater; that 

 is, the gradual running off of the wave or tide. At the sides of the 

 slab are continuous channels and accessory markings ; scratches and 

 bruises of the sand are also evident. 



[214] 



