The Story of the Kremmling Ammonite Site and a Painting by Wayne Itano, Guest Blogger

Today, we have a very exciting post for you: a guest post from paleo-enthusiast Wayne Itano!  Here is a bit of background on Mr. Itano:  

Wayne Itano is a physicist at NIST (National Institute of Standards and Technology) in Boulder, CO.  He has a hobby interest in paleontology and is also a curator adjoint at the Natural History Museum of the University of Colorado.

Today, Mr. Itano is going to tell us about the Kremmling Ammonite Site.  Join me in giving him a warm welcome!  Let's get started!

The Kremmling Cretaceous Ammonite Locality lies on BLM (Bureau of Land Management) land to the north of the little town of Kremmling, in Grand County, Colorado.  It was first noticed for the very high concentration of very large ammonites(ammonites are extinct relatives of the modern chambered nautilus and were probably more closely related to octopi and squids).  It has been protected since the 1980s.  It was written up in the book “Cruisin’ the Fossil Freeway” by the paleontologist Kirk Johnson and the artist Ray Troll.

Dr. Kirk Johnson, formerly of the Denver Museum of Nature and Science, is now head of the Smithsonian Museum of Natural History.

Ray Troll is an artist with a special interest in natural history and ancient life.  Here is his painting “Night of the Ammonites” inspired by a visit to the Kremmling Ammonite Locality.

Artist Ray Troll’s picture of the Kremmling area, about 73 million years ago, during the Cretaceous Period, when most of Colorado was beneath the sea.  Picture Credit: Ray Troll

The large disk-shelled creatures are ammonites called Placenticeras.  The ones with narrow, straight, tapered shells are another kind of ammonite, called Baculites. The sharp-toothed swimming reptiles are called mosasaurs.  We have evidence from bite marks on ammonite shells that mosasaurs preyed on Placenticeras.  Over on the left are some strangely shaped small ammonites called Anaklinoceras.

The Kremmling site was featured by Earth Magazine, in a kind of online quiz called “Where on Earth.”  The page with the question and answer is HERE.

If you want to visit the Kremmling site, first pay a visit to the BLM office at 2103 E. Park Avenue, Kremmling.  They can advise you on road conditions.  At times it can be inaccessible, even for 4-wheel drive vehicles. Here is a sign at the site:

Warning sign at the Kremmling Ammonite protected area.  Photo Credit: Wayne Itano

Here is an informational sign.  Collecting is prohibited within the site, but there are nearby areas where collecting is allowed.  Inquire at the BLM office.

Explanatory sign at the Kremmling site.  Photo Credit: Wayne Itano

The area is littered with boulders containing the impressions of giant Placenticeras ammonites.  The fossils themselves have been collected, many to museums.  Intact boulders containing ammonites lie under the surface and could be studied in the future.

Boulders with impressions of Placentideras ammonites.  Photo Credit: Wayne Itano

Baculites (straight ammonites) are also rather common. 

A Placenticeras ammonite impression with a Baculites fossil (cylindrical object) on the same boulder.  Photo Credit: Wayne Itano

Large clams called Inoceramus are rather common.  Here are some examples.

A large Inoceramus clam fossil.  Photo Credit: Wayne Itano

A boulder with impressions of Inoceramus clams.  Photo Credit: Wayne Itano

Emmett Evanoff, a professor at the University of Northern Colorado in Greeley, has been studying the paleontology of this area.  One odd thing is that the great majority of the Placenticeras fossils are of females.  (The males are distinguished by being much smaller and having coarse ribs on their shells.) He thinks this might have been a nesting site.  The males would have fertilized the eggs and then left, leaving the females to guard the eggs.  Katie DeBell was a student of Emmett’s who mapped out the ammonites on the surface and seems to know them all by number.  She lives in Kremmling and often gives tours, especially to school groups.  Here she is, pointing out some features of one of the ammonites.

Katie DeBell explaining some features of an ammonite in 2011.  Photo Credit: Wayne Itano

I have a vacation house in the mountains not far from Kremmling.  I happen to know a painter who is also a fossil enthusiast, named Terry McKee.  I commissioned him to do a painting of the Kremmling site when it was an ammonite nesting ground.  I also asked Dr. Evanoff for advice, and the three of us met to plan the painting.  Here it is, and the original is now hanging in my mountain house.

Painting of the Kremmling Ammonite nesting site.  The large ammonites are guarding their eggs.  Baculites and various smaller ammonites, swim above.  The small round ammonite on the left, facing left, between two of the straight baculites, is a male Placenticeras.  A mosasaur lurks in the background.  Picture Credit: Terry McKee

- Wayne Itano

Thank you very much, Mr. Itano, for the post!  The post was really interesting, and I know I learned a lot!  I found the part about the nesting site particularly interesting!  I have no doubt that my readers, as well as myself, would love to hear from you in the future!  Thanks again! - Zack Neher

Bronze Tree on Dwellable