Bohor, B. F.; Foord, E. E.; Modreski, P. J., and Triplehorn, D. M. "Mineralogic Evidence for an
Impact Event at the Cretaceous- Tertiary Boundary," Science 224 (25 May 1984), pp. 867-868.
Here are USGS people reporting on their analysis of a layer of deposit which seems to indicate
that the period in which it was laid down was one characterized by an impact with an object from
space: a comet, an astroid, or "something." The extinction of species at the time could, thus, be
attributed not to volcanic activity but to a catastrophe, a collision with an object from space.
There is clear evidence here that impacts have occurred through time but this is the first time we
have evidence that catastrophe resulted from the impact. Catastrophists can take heart with the
publication of these data.