The previously reported plant fossils at Dinosaur Ridge, Morrison, Colorado, are a mixture of broken charcoal pieces and their impressions, silt and sand. Normal sedimentation processes at a forest fire site indicated that buoyancy differences should strongly limit the mixing of sand and charcoal. Catastrophic mud or debris flows were suggested as the appropriate mechanism for much of the Dinosaur Ridge plant fossil deposit. The contents of a catastrophic debris flow from the Storm King Mountain forest fire site at Glenwood Springs, Colorado, were examined to determine any similarities with the Dinosaur Ridge site. Charcoal fragments were found mixed throughout two cores taken from the mud flow component of the deposit. Two cores from other areas which experienced normal sedimentation conditions showed no mixing of sand and charcoal. These differing depositional frameworks are suggested as a basis for distin'guishing between slow and catastrophic sedimentation rates.