  We compare the propagation of iron and proton nuclei above 10^19 eV in a
structured Universe with source and magnetic field distributions obtained from
a large scale structure simulation and source densities about 10^(-5) Mpc^(-3).
All relevant cosmic ray interactions are taken into account, including
photo-disintegration and propagation of secondary products. Iron injection
predicts spectral shapes different from proton injection which disagree with
existing data below about 30 EeV. Injection of light nuclei or protons must
therefore contribute at these energies. However, at higher energies, existing
data are consistent with injection of pure iron with spectral indices between 2
and 2.4. This allows a significant recovery of the spectrum above roughly 100
EeV, especially in the case of large deflections. Significant auto-correlation
and anisotropy, and considerable cosmic variance are also predicted in this
energy range. The mean atomic mass A fluctuates considerably between different
scenarios. At energies below 60 EeV, if the observed A > 35, magnetic fields
must have a negligible effect on propagation. At the highest energies the
observed flux will be dominated by only a few sources whose location may be
determined by next generation experiments to within 10-20 degrees even if
extra-galactic magnetic fields are important.
