SANTA MARIA TO LOS ARROYOS 129 



to be eddy spots, or areas where the currents meet 

 and, becoming confused, release their cargoes of 

 sand and other material derived from the nearby 

 reef. The configuration of the bars is invariably 

 lengthwise with the direction of the current, and 

 attenuate at both ends. The very small part of 

 the bars usually exposed are gradually building up 

 by wave action. These bars now form the chief 

 obstruction to navigation by larger vessels of the 

 reef-enclosed waters. 



Between the mangrove islands projecting out 

 from the shore at intervals of two or three miles 

 the depth of the intervening bays is very uniform, 

 shelving gently from shore to about four fathoms, 

 mud and sand bottom. In the area between the 

 ends of the mangrove islands and the reef the 

 normal depth increases to five or six fathoms and 

 is uniform and continuous save for the occasional 

 interruption of the fairway by the sand flats and 

 bars already described. The bottom within this 

 area is more diversified, but is usually a mixture of 

 coarser sand and finer mud in varying proportions. 

 The bottom, in general, even close to the shore 

 beaches, seems to be composed far more of material 

 derived from the reef than it is of sediments from 



