concave. It is expected that at the depth (1,929 meters) of ripple occurrence in the 

 TOTO, either internal waves or tidal oscillations produced the ripple marks observ- 

 able, although the latter is more likely. 



As mentioned above, adjacent to and south of the ripple-marked area is pebble- 

 and cobble-sized debris which probably has been derived from the reef areas bounding 

 the channel. From the photograph in Plate XI the ripple marks are apparent, and close 

 study of the photograph shows the finer material to be encroaching upon the larger 

 debris. The distribution of pebble and gravel material around the large cobble-sized 

 fragment in the upper right-hand half of this photograph suggests a strong southerly 

 current which is producing a lag deposit in this area with a net movement of sediment 

 toward the south. 



63 



