North of this survey area, seismic data (Ewing et al, 

 1950) indicate the existence of a ridge on the surface of the 

 crystalline basement. The possibility has been considered 

 that this ridge may extend into the survey area and may be the 

 source of the magnetic anomalies found in the vicinity of the 

 continental slope. However, King et al (1961) computed values 

 of the magnetic polarization intensity that this ridge would 

 be required to have in order to produce the magnetic anomalies 

 observed over it. These computed values were too large to be 

 plausible. 



In the southern part of the survey area, the magnetic 

 anomalies peak more sharply. This phenomenon may indicate a 

 shallowing of the basement in that region. 



It appears that the most probable general explanation for 

 the continental slope magnetic anomaly is that advanced by 

 King et al (1961). These investigators suggest that although 

 basement topography probably contributes to the magnetic pro- 

 file, the continental slope magnetic anomaly may be partly the 

 expression of a large mass or series of masses of more highly 

 magnetic rocks within the basement. 



Another significant feature is the relative position of 

 the peak of the magnetic anomaly. Profiles H-H' and I-I' 

 (Figures 11 and 12) are representative of the southern part of 

 the survey area. These profiles show the peak of the anomaly 



