Number 9 (Story #2), November 20, 1990 by Phillip F. Schewe and Ben Stein DID A METEOR IMPACT KILL THE DINOSAURS? An enhanced level of iridium and the presence of shocked materials in strata corresponding to the boundary between the Cretaceous and Tertiary eras some 65 million years ago has led some scientists to believe that the mass extinction of life forms at that time occurred in the aftermath of a large comet or asteroid impact. Alan Hildebrand of the University of Arizona (602-621-4655) reports evidence for such an event in the form of glass droplets (tektites) and shocked quartz crystals in an area centering around the Yucatan Peninsula. Hildebrand is also searching for large craters in the Colombian basin. (New Scientist, Nov. 17.)