CO emission in directions of some millimeter wavelength continuum sources

Observations of emission at 2.6 mm from /sup 12/CO, /sup 13/CO, and C/sup 18/O from the nearby dark clouds L255, L673, L1471, and L1613 permit calculations of their molecular column densities for both CO and H/sub 2/. Two of these clouds, L1613 and L673, are known to emit continuum radiation at millimeter wavelengths: presumably from embedded heated dust grains. The continuum emission correlates with the spatial distribution of the molecular column densities.