  We investigate the extinction together with the radial velocity dispersion
and distribution of red clump stars in the anti-center direction using spectra
obtained with Hectospec on the MMT. We find that extinction peaks at
Galactocentric radii of about 9.5 and 12.5 kpc, right in front of the locations
of the Perseus and Outer arms and in line with the relative position of dust
and stars in external spiral galaxies. The radial velocity dispersion peaks
around 10kpc, which coincides with the location of the Perseus arm, yields an
estimated arm-interarm density contrast of 1.3-1.5 and is in agreement with
previous studies. Finally, we discover that the radial velocity distribution
bifurcates around 10-11 kpc into two peaks at +27 km/s and -4 km/s. This seems
to be naturally explained by the presence of the outer Lindblad resonance of
the Galactic bar, but further observations will be needed to understand if the
corotation resonance of the spirals arms also plays a role.
