  We have applied the method of Zeeman tomography to analyze the surface
magnetic field structures of the white dwarfs PG 1015+014 and HE 1045-0908 from
spin-phase resolved flux and circular polarization spectra obtained with FORS1
at the ESO VLT. We find for both objects field topologies that deviate
significantly from centred dipoles. For HE 1045-0908, the frequency
distribution of magnetic field strengths is sharply peaked at 16 MG for all
rotational phases covered by our data but extends to field strengths at least
five times this value. In the case of PG 1015+014 there are significant
contributions to the frequency distribution in the range from 50 to 90 MG with
the maximum near 70 MG. The detailed shape of the frequency distribution is
strongly variable with respect to the rotational phase.
