  The reaction $^{12}C(\nu_\mu,\mu^-) X$ has been measured near threshold using
a $\pi ^+$ decay-in-flight $\nu_\mu$ beam from the Los Alamos Meson Physics
Facility and a massive liquid scintillator neutrino detector (LSND). In the
energy region $123.7 < E_\nu < 280$ MeV, the measured spectral shape is
consistent with that expected from the Fermi Gas Model. However, the measured
flux-averaged inclusive cross section ($(8.3 \pm 0.7 stat. \pm 1.6 syst.)
\times 10^{-40} cm^2$) is more than a factor of 2 lower than that predicted by
the Fermi Gas Model and by a recent random phase approximation calculation.
