Ammonites and Their Cousins

Predators of the Cretaceous

Dennis Gertenbach

Dennis Gertenbach

Western Interior Paleontological Society, Colorado School of Mines Geology Museum

Ammonites became the dominant invertebrate predators in the Jurassic and Cretaceous (200-66 million years ago). In the Western Interior Seaway that covered part or all of Colorado during this time, ammonites reached their peak size and diversity. But, where did these creatures come from and why did they suddenly disappear at the end of the Cretaceous? Dennis will give an overview of the evolution of ammonoids (ammonites and their close relatives) and nautiluses. Their diversity and value as bio-stratigraphic markers will be discussed, along with current thoughts about why ammonites died at the end of the Cretaceous, and an overview of some ammonite localities in Colorado.

Dennis’ passion is invertebrate fossils–collecting, identifying, and learning how fossils help us understand the earth in ancient times. He has been a member of the Western Interior Paleontological Society (WIPS) since 1999 and the Flatirons Mineral Club in Boulder (FMC) since 1995, is a past president of both, and leads the children’s programs and field trips in each organization. He formed the WIPS Invertebrate Study Group where members help each other learn more about invertebrate fossils and explore new fossil collecting areas. He also leads a group of volunteers helping to catalogue the fossil collection of the Colorado School of Mines Geology Museum which houses fossils collected from the late 1800s to the present. Dennis earned his Ph.D. in Chemical Engineering and works part time as a vice president at Hazen Research, an engineering firm in Golden.

This talk is appropriate for all ages 10 years old and older, and those young folks will be entertained.  No scientific background is necessary to enjoy this presentation.

October 8, 2016     10:00 – 11:30
Cañon City Public Library, 516 Macon, Cañon City
Fremont Fall Heritage Festival

(719-275-9781 for more information)