31 



28*i0 112' 



DEPIH CONTOURS 



Fig. 8. Sediment distribution for the Costa de Hermasillo region, south of Tiburon Island. 



Depth and sediment countours based on a chart drawn up by Joseph R. Curray, Scripps 



Institution. Shelly zone added by this author. 



construct from the available data, except for the two broad portions stu- 

 died by Curray in van Andel, et. al. (1964, in press). On the west side,the 

 bottom is primarily rock, gravel and sand. There is no source of fine 

 sediment, and with the steep sides of the shoreline and violent weathering, 

 one can expect to find only coarse to very coarse sediments. As mentioned 

 before, the northern portion of the Gulf continental shelf is characterized 



