  The halo structure at high Galactic latitudes near both the north and south
poles is studied using SDSS and SuperCOSMOS data. For the south cap halo, the
archive of the SuperCOSMOS photographic photometry sky survey is used. The
coincident source rate between SuperCOSMOS data in $B_J$ band from $16^m.5$ to
$20^m.5$ and SDSS data is about 92%, in a common sky area in the south. While
that in the $R_F$ band is about 85% from $16^m.5$ to $19^m.5$. Transformed to
the SuperCOSMOS system and downgraded to the limiting magnitudes of
SuperCOSMOS, the star counts in the northern Galactic cap from SDSS show up to
an $16.9\pm6.3%$ asymmetric ratio (defined as relative fluctuations over the
rotational symmetry structure) in the $B_J$ band, and up to $13.5\pm6.7%$
asymmetric ratio in the $R_F$ band. From SuperCOSMOS $B_J$ and $R_F$ bands, the
structure of the southern Galactic hemisphere does not show the same obvious
asymmetric structures as the northern sky does in both the original and
downgraded SDSS star counts. An axisymmetric halo model with n=2.8 and q=0.7
can fit the projected number density from SuperCOSMOS fairly well, with an
average error of about 9.17%. By careful analysis of the difference of star
counts between the downgraded SDSS northern halo data and SuperCOSMOS southern
halo data, it is shown that no asymmetry can be detected in the south Galactic
cap at the accuracy of SuperCOSMOS, and the Virgo overdensity is likely a
foreign component in the Galactic halo.
