Photo courtesy of Dr. David Archibald
Professor of Biology at San Diego State University

Above: The arrows point to the K/T boundary. The "K" comes from the German spelling for Cretaceous.

Below: Jordan is the county seat of Garfield County (yellow), located in the center of eastern Montana.

Map courtesy of Natural Resource Information System
State Library of Montana

Interested in learning more about mass extinctions? . . .
The June 1989 issue of National Geographic Magazine has an extensive article called "The March Toward Extinction".