  We present our results from the Southern Galactic Plane Survey, an effort to
map the fourth quadrant of the Milky Way in linear polarization at a frequency
of 1.4 GHz and at a resolution of 1-2 arcmin. These data are a powerful probe
of both the turbulence and large-scale structure of magneto-ionic gas, and have
revealed a variety of new features in the interstellar medium.
