  A higher--twist nuclear enhancement of $R = \sigma_L/\sigma_T$, as might be
expected to arise due to fermi motion and whose magnitude is within the
error-bars of recent experiment, is shown to lead to a monotonic {\it decrease}
in the ratio of nuclear vs. nucleon cross--sections at small Bjorken $x$ for
{\it increasing} $Q^2$. This effect at small $x$, comparable in magnitude to
those reported for shadowing, is driven mainly by kinematic factors and
essentially vanishes for $x > .1$. Its unusual $Q^2$ dependence rather
complicates the unravelling from present data in the shadowing region the
corresponding dependence in $Q^2$ of the nuclear structure functions,
$F_2^{A}(x,Q^2)$.
