  We have detected extraplanar cold dust at distances out to > 10 kpc, situated
in the halo of the interacting galaxy NGC 4631. The dust emission disk is much
thinner than the warped HI disk and new structures emerge. In particular, a
giant arc has been found that is linked to anomalies in the kinematical
structure of the atomic gas. Most of the extraplanar dust is closely associated
with HI spurs that have been found earlier. These spurs obviously are traces of
the interaction. The dust emission within the plane reaches the border of the
optical disk.
  The activity of the disk of NGC 4631 is moderately enhanced by the
interaction, but no gas moving in the z-direction could be found. Hence, it
seems unlikely that strong winds have deposited the high-z dust. Instead, the
coincidence with the HI features suggests that we see a track left behind by
the interaction. In addition, the HI shows a supershell formed by an impact in
the zone where the dust trail crosses the disk. This region is also
characterized by disturbances in the distribution of the Ha light. The masses
associated with the dust can be estimated only very roughly on the basis of the
existing data; they are of the order of a few 10^9 M_o of gas.
