The properties of Galactic molecular clouds tabulated by Solomon et al. (SRBY; 1987ApJ...319..730S) are re-examined using the Boston University-FCRAO Galactic Ring Survey of ^13^COJ=1-0 emission. These new data provide a lower opacity tracer of molecular clouds and improved angular and spectral resolution compared with previous surveys of molecular line emission along the Galactic Plane. We calculate giant molecular cloud (GMC) masses within the SRBY cloud boundaries assuming local thermodynamic equilibrium (LTE) conditions throughout the cloud and a constant H_2_ to ^13^CO abundance, while accounting for the variation of the ^12^C/^13^C with galactocentric radius.