  We extend the McLerran-Venugopalan model for the gluon distribution functions
of very large nuclei to larger values of the longitudinal momentum fraction xF.
Because gluons with larger values of xF begin to resolve the longitudinal
structure of the nucleus, we find that it is necessary to set up a fully
three-dimensional formalism for performing the calculation. We obtain a
relatively compact expression for the gluon number density provided that the
nucleus is sufficiently large and consists of color-neutral nucleons. Our
expressions for the gluon number density saturate at small transverse momenta.
The nuclear dependence we obtain is such that the number of gluons increases
more slowly than the number of nucleons is increased.
