  We report the observation of a doubly-periodic surface defect-pattern in the
liquid crystal 8CB, formed during the nematic--smectic A phase transition. The
pattern results from the antagonistic alignment of the 8CB molecules, which is
homeotropic at the surface and planar in the bulk of the sample cell. Within
the continuum Landau-deGennes theory of smectic liquid crystals, we find that
the long period (~10 \mu m) of the pattern is given by the balance between the
surface anchoring and the elastic energy of curvature wall defects. The short
period (~1 \mu m) we attribute to a saddle-splay distortion, leading to a
non-zero Gaussian curvature and causing the curvature walls to break up.
