Previous work then, indicates the geologic factors which may 
contribute to the anomalies over the continental margins. In order 
to magnify and delineate the REARING ‘erceméls of Zone 3, the total 
magnetic intensity (fig. 4) was subjected to a Gram or Chebyshev 
orthogonal polynomial fitting technique (Van Voorhis and Davis 1964). 
Specifically, the total intensity along selected track lines, ter- 
minated just below Physalia seamount, was fitted with a 5th-degree 
polynomial. The residual (the difference between the observed in- 
tensity and the polynomial curve) was then contoured at a 50-gamma 
interval (fig. 8). Due to the high degree of the polynomial, the 
amplitudes of the residuals are quite different from those which 
would be obtained from removal of an earth's regional field. For 
the purposes of this report, emphasis is placed only on the trend 
characteristics as brought out by this procedure. 
The trends associated with observed anomalies are designated as 
A, B and C on figure 8. The trends of the right half of the area 
strike 40-45 east. A and B terminate against the seamount features, 
and the A continues at a strike of 70-80" east along 4O°N latitude. 
The apparent offset in A, of about 30 miles, is attributed to the 
aforementioned transcurrent faulting. Trend C is continuous along 
the top of the area. 
Depth estimates and the general correlation between the direction 
of the anomaly trends and the basement structural trends reflected 
