Bathymetric data were obtained with a Precision Depth Recorder 

 (MK XI) and an AN/UQN 1-C sonar sounding set using an unstabilized 

 transducer. 



III. DATA PROCESSING 



All magnetic data were scaled for absolute values of total intensity 

 in gammas using a specially constructed conversion template. These 

 values for the survey area then were plotted on a 1: 500,000-scale 

 track chart. Using this chart, a total magnetic intensity contour 

 chart (figure 3) was constructed with a contour interval of 50 gammas. 



A regional magnetic intensity contour chart for the southern 

 Bahama Area is shown in figure 4. Regional magnetic intensity contours 

 were obtained by graphically smoothing the total intensity contours. 



To amplify the trends and character of the magnetic anomalies, a 

 residual magnetic intensity contour chart was constructed (figure 5). 

 This residual chart was prepared by removing the regional magnetic 

 intensity values from the observed total intensity values. 



Magnetic data were not corrected for temporal variations of the 

 earth's magnetic field. The cross-check lines run in the survey area 

 indicate that temporal variations were less than the contour interval 

 chosen. San Juan Magnetic Observatory records show that no major 

 magnetic disturbances occurred during the entire survey period. 



A bathymetric contour chart (figure 6) was constructed at the 

 same scale as the above charts and has a contour interval of 20 fathoms. 

 No sound velocity or other corrections have been made to the bathy- 

 metric data. 



