Where on Earth? - April 2011

Clues for April 2011:
1. Giant ammonites and other marine invertebrates once inhabited a vast, Cretaceous-period sea that covered much of North America. Today, a state park located where part of the sea once was contains the highest concentration of giant ammonite fossils in the world.
2. The fossils are found in sandstone slabs and outcrops, forming circular depressions or molds. Some are as large as 60 centimeters in diameter; in total, there are more than 300 rocks with impressions of ammonites.
3. It is not known exactly why the concentration of ammonites at this site is so large; some scientists speculate that a catastrophic event such as a tidal wave or hurricane occurred 72 million years ago that drove the creatures onto a sandbar, where they died. Others suggest that the site might have been a brooding ground for female ammonites.
Name the park and its home state.
Scroll down for the answer
Answer: The Kremmling Cretaceous Ammonite Locality in Colorado contains the highest concentration of giant ammonite fossils in the world, as well as many other marine invertebrates such as nautiloids, bivalves and gastropods. The region was once the bottom of a large sea that separated what is now the eastern United States from the western U.S. Photo by Katie DeBell.
April winners
Mark Brashear (Monroeville, Pa.)
Ken Fantone (Fort Collins, Colo.)
Art Johnson (Kenner, La.)
Maggie May Roll (Gansevoort, N.Y.)
Elisabeth Widom (Oxford, Ohio)

To submit your photographs to our Where on Earth? contest, send them via e-mail to

01 Apr 2011