The red reflector was previously reported by Meisburger and Duane (1969) as an 

 extensive acoustic horizon of regional significance underlying the Atlantic inner shelf off 

 Florida. This reflector is easily recognized inshore between the Georgia border and Flagler 

 Beach because it overlies distinctive seaward-dipping internal reflectors in unit B and also 

 truncates unit D and parts of unit E over the Daytona Beach high (Figs. 13, 14 and 15). 

 From near False Cape southward, a reflector judged to be continuous with the red reflector 

 is directly underlain by unit F having seaward-dipping internal reflectors. Meisburger and 

 Duane (1971) and Field and Duane (1974) have discussed the red reflector in the Cape 

 Canaveral area and southward. 



A contour map on the surface of the red reflector is shown in Figures 14 and 15. The 

 overall slope of the red surface is generally eastward about 3 feet per nautical mile. The red 

 reflector is judged to be an erosional unconformity because it truncates internal reflectors of 

 underlying units and progressively overlies older units to the south. 



The white reflector like the overlying primary reflectors slopes consistently eastward 

 (Fig. 17). Within study limits the slope of the white surface averages about 8 feet per 

 nautical mile. In the north it overlies unit C and southward of the pinchout of that unit it 

 overlies unit D. Throughout its extent the white reflector is overlain by unit B and can 

 readily be located inshore by its position at the base of the distinctive seaward-dipping 

 internal reflectors of unit B. The wliite reflector is judged to be an erosional unconformity 

 because it transgresses two distinct units and truncates internal reflectors in these units. 



The purple reflector in the northern part of the study area is rarely visible because of 

 multiples and perhaps insufficient acoustic contrast between bounding units. Therefore, it is 

 primarily an inferred surface between the white and purple units and its position can only 

 be approximated in most places. Southward of the pinchout of unit C the purple reflector is 

 supplanted by the presumably younger white reflector (Fig. 14). 



The deepest reflection surface which can be continuously followed throughout the study 

 area is the green reflector. Like the red reflector it is of regional significance and has been 

 identified in seismic reflection profiles as far soutli as Fort Pierce (Meisburger and Duane, 

 1969, 1971; Field and Duane, 1974). 



In the northern part the green reflector dips northeastward. South of St. Augustine the 

 dip is predominantly eastward (Figs. 18 and 19). Slopes vary from near horizontal to 40 feet 

 per statute mile with an average in most places of 6 feet per nautical mile. The green 

 reflector surface map in Figures 18 and 19 depicts the broad structural trends related to the 

 high off Daytona Beach and many of the larger fluxures which affect units D and E in 

 particular and in places the overlying units. The marked increase in the slope of the green 

 surface evident from about 28°45'N. to south of Cape Canaveral may also be structural in 

 origin. The projected alinement of this slope north of 28°45'N. places it eastward of the 

 survey area and how far the slope extends to the north is unknown. 



37 



