  We present interferometric observations of CO J=1-0 emission in the central
regions of the edge-on galaxy NGC 4631, known for its extended gaseous halo and
its tidal interactions. Previous single-dish observations revealed that almost
all of the CO emission arises from a central ring or bar-like structure of
length $\sim$ 4 kpc. We confirm this structure at higher resolution, and find
that it is bent at the center, reflecting the overall bend in this galaxy
apparent from optical images. The kinematic evidence favors a rigidly rotating
ring over a bar. The gaseous halo emission in several tracers is concentrated
above and below this molecular structure. To the north of an emission peak at
the eastern end of the structure is an extraplanar feature showing filamentary
and shell-like properties which we interpret as an energetic molecular outflow.
The energies involved are difficult to estimate, but are probably of order
10$^{54}$ ergs or more. The CO concentration in the disk below this structure
coincides with a bright HII region complex, a peak of radio emission, and the
brightest X-ray feature in the inner disk of the galaxy seen in a ROSAT HRI
map, all suggesting intense star formation. A filament of radio continuum
emission may also have a footprint in this region of the disk. The origin of
the outflow is unclear.
