  We present spatially resolved mid-IR spectra of NGC 1068 with a
diffraction-limited resolution of 0.25\arcsec using the Long Wavelength
Spectrometer (LWS) at the Keck I telescope. The mid-infrared image of NGC 1068
is extended along the N-S direction. Previous imaging studies have shown the
extended regions are located inside the ionization cones indicating that the
mid-infrared emission arises perhaps from the inner regions of the narrow-line
clouds instead of the proposed dusty torus itself. The spatially resolved
mid-IR spectra were obtained at two different slit position angles, +8.0 and
-13.0 degrees across the elongated regions in the mid-IR. From these spectra,
we found only weak silicate absorption toward the northern extended regions but
strong in the nucleus and the southern extended regions. This is consistent
with a model of a slightly inclined cold obscuring torus which covers much of
the southern regions but is behind the northern extension. While a detailed
analysis of the spectra requires a radiative transfer model, the lack of
silicate emission from the northern extended regions prompts us to consider a
dual dust population model as one of the possible explanations in which a
different dust population exists in the ionization cones compared to that in
the dusty torus. Dust inside the ionization cones may lack small silicate
grains giving rise to only a featureless continuum in the northern extended
regions while dust in the dusty torus has plenty of small silicate grains to
produce the strong silicate absorption lines towards the nucleus and the
southern extended regions.
