c. Inner-Shelf Plain - The inner-shelf plain is characterized by 

 its extremely gentle seaward inclination, narrow depth range (nearly 

 all the area is between -40 to -70 feet MLW) and its general alignment 

 parallel to the northwesterly trend of the shoreline. 



Morphologic features on the inner-shelf plain consist of a series of 

 platforms or step-like flats (areas of reduced gradient), gentle slopes 

 leading from one level to the next, and shoals. With few exceptions these 

 features are not topographically prominent, and many are not evident on 

 small or medium-scale charts. 



Charted depths over the flats generally lie within ±5 feet of the 

 average depth. The most irregular of those flats is the 50-foot flat 

 which contains a large number of shoals in the section south of Sebastian 

 Inlet (27°52'N). Inshore, the lower slopes of the shoals c6alesce to form 

 an irregular plateau- like inner level with depths of 30 to 40 feet MLW. 

 Accretion in Canaveral Bight has also produced a higher, but smooth- 

 surfaced, inner level of the 50- foot flat at around -40 feet MLW. Other 

 flats on the shelf are generally less complex and contain few shoals. 



Shoal ridges and hills are most extensively developed on the inner 

 shelf south of Sebastian Inlet (Figure 5). Nearly all these shoals are 

 linear and most have a north or northeasterly alignment. Two exceptions 

 are Thomas -Shoal off Sebastian Inlet and an unnamed smaller ridge between 

 St. Lucie Shoal and Capron Shoal. These shoals lie with a northwesterly 

 alignment suggesting possibly different genetic processes or time of 

 formation. In profile, inner-shelf shoals show a smooth regular surface, 

 and both symmetrical and asymmetrical cross-sectional form. Where asym- 

 metry exists, the steeper flanks face east or southeast. Seismic data 

 indicate the shoals to be superposed on the surface of the flat. 



d. Outer- She If Zone - Little is known of the composition and 

 topography of the outer-shelf zone. Published hydrographic charts show 

 deeper parts of the outer shelf at a scale too small for any but gross 

 definition of bottom topography. Large-scale coverage to depths of about 

 130 feet permits definition of the main shelf features, but does not 

 detail the irregular bottom. A survey of Florida's offshore fisheries 



by Moe (1963) contains much valuable general information on the bottom 

 characteristics of outer shelf fishing grounds. Cores and geophysical 

 lines obtained for this study are mostly from the inner margin of the 

 Continental Shelf with few reaching the outer zone. 



Available information shows that the outer shelf is dominantly a 

 zone of highly discontinuous broken topography of generally low relief 

 (10 to 20 feet). Moe (1963) documents descriptions of numerous rocky or 

 coral reef patches, ridges, ledges, cliffs and depressions. These data, 

 provided by fishermen who frequent these grounds, indicate that the 

 angularity of many relief features is a striking characteristic. Linear 

 trends of ridges or abruptly steepening slopes are characteristic of the 



