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final interprclation nuS١ await further xcavation. Some of the conductivity
pattcrns sce١ in the tr٨٧٥rSeS may be a result of presently covcrcd cxcavation pits
derived fron carlier archcological cxpcditions. The ncccssary rccords have been
unohtainable up to ١ow rcgarding thcse crlier cxcavations, Our idcntification of
the canal has, for this rcason, not bcen clcarly verificd. We have bcen collccting
mcasureICnIs in areas whcre we know archacological cxcavations hiave bccn
conductcd carlier, which show similar drops in thne conductivity pattcrns. Since we
do not have a clcar idea of whcre the excavators in the 1950s a١d 1960s carricd out
all of their cxcavations, sone of thc greater variability in thc conductivity patterns
may be caused partly or fully by such unknown excavation pits.

Tvo grids were mcasurcd (Figure ‫ )ﺍ‬Grid No. 1 is located north of the
Portuguese fortress and west of the lslamic fortress. It measures 43 by 75 meters
and is partly cut to the southwest by thc moat system of the Portuguese fortress.
Grid No. 1 was measured with both vertical and horizontal dipole configurations,
resulting in accumulative depth penetration of 6 and 2 meters, respectively. The
total number of measurements for the vertical mode is 2646, excluding previously
excavated areas and areas covered by the dry moat. In both modes, the dipole
direction and the measuring (walking) direction was north-south. The total number
of measurements for the horizontal mode is 2125, with similar exclusions as seen in
the vertical mode recording. Figures 5, 6 show the plot's isometric projections of
the conductivity variation in the vertical and horiontal modes, respectively, The
isometric projections have been smoothed by the CPS-1 software to allow a general
display of the major variations of the conductivity. Figures 7, 8 show the same data
expressed in 2- dimensional contour plots. The empty area in the upper right square
is caused by the moat system surrounding the Portuguese fortress (2ero values).
Also, the empty square located to the left of the center is caused by earlier
excavation; thus no measurements were taken.

When comparing the two contour maps we suggest that the variation in the
conductivity is better developed in the vertical mode when compared to the
horizontal mode, This can be noted around the center of the grid, where it is
evident that a large area yields a higher conductivity when compared to the
peirpheral areas. In order to veriyf and understand some of the variation, a 40
meter long and 2.5 meter wide test pit .was excavated from the eastern border
toward the center of the square. The excavation, which in some areas extended
more than 8 meters below the surface before yielding sterile strata, yielded an
extensive amount of man-made sturctures represented by stone walls and burials.
Similarly, the same structures yielded multiple stratigraphical layers representing
different occupational phases.

Based on our test excavation and the wto plots depicting tihe 6 meter and 2 meter
penetration, it was clear that it would be quite difficult to correlate the conductivity
pattern with the actual archaeological finds in the ground because of the extensive

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