100 300 



500 700 900 1,100 1,300 1,500 1,700 

 DISTANCE FROM SHORE (m) 



Figure 1. Profile of shelf morphology off Hillsboro Beach, Florida. 



The study site, located approximately 1.6 kilometers south of the 

 Deerfield Beach fishing pier (Fig. 2), has three such reef lines. The 

 first is a low profile reef, 30 to 40 meters wide in a water depth of 5 

 to 6 meters. The inshore edge of the reef is approximately 100 meters 

 from shore. Shoreward of the edge is a sand area with a series of 

 scattered limestone outcrops and wormrock colonies of Phragmatopoma 

 lapidosa. 



The inshore edge of the second reef, which is 180 to 190 meters 

 wide, is approximately 740 meters from shore at a depth of 10.5 to 12.5 

 meters. The outer edge of this outcrop drops to a depth of approxi- 

 mately 20 meters. 



Between the second and the third reefs is a relatively flat sand 

 area approximately 500 meters wide. The third reef, located at a depth 

 of 15 to 26 meters forms the seaward edge of the Continental Shelf 

 (Duane and Meisburger, 1969). Beyond the third reef, the sandy bottom 

 slopes relatively steeply to the floor of the Florida Straits. 



Duane and Meisburger (1969) described the sediments within the 

 sandflats as white to gray calcareous skeletal sands and gravel. These 

 sediments are believed to have been produced in situ, and include 

 fragments from marine algae, mollusks, foraminiferans, bryozoans, and 

 corals. Also present are small amounts of echinoid spines, sponge 

 spicules, alcyonarian sclerites, and worm tubes. The dominant 

 nonskeletal materials include rod-shaped and elliptical pellets 

 (probably fecal), semiconsolidated calcarenite oolites, and aggluti- 

 nated worm tubes. 



