Eighty-five million years ago, a vast ocean called the Western Interior Sea covered the area now known as Kansas. When the water receded, it left behind a fossil record revealing that the sea had once been teeming with life. Oceans of Kansas, by Michael J. Everhart, explores the animals that once lived in this ancient sea. Commentator Rex Buchanan reviews the newest edition of this landmark book.
Commentator Rex Buchanan is a writer, traveler and director emeritus of the Kansas Geological Survey. He lives in Lawrence.
In the world of geology, Kansas is well known for big vertebrate fossils from the chalk beds out west. Museums around the world display those remains. Now there's a new edition of the most comprehensive, authoritative book on those animals and the ancient sea that produced them. Oceans of Kansas: A Natural History of the Western Interior Sea, is by Michael J. Everhart, published by the Indiana University Press.
If you're a fan of fossils from out west, Everhart has you covered. He focuses on the Cretaceous Period of geologic history, mainly looking at a slice of the Cretaceous from about 85 million years ago. Western Kansas was beneath an ocean that was, at most, 600 feet deep, and warm, much like today's Gulf of Mexico. Single-celled animals flourished in that sea, died, and rained down to the bottom, depositing a mucky ooze at the rate of about an inch every 700 years.
The ooze became chalk, providing the perfect medium for preserving animals that died and drifted to the sea floor. The variety and size of those animals is staggering.
There were sharks, some bigger than today's great white, apparently lots of them based on all the teeth left behind. There were fish, including the giant Xiphactinus that grew to nearly 20 feet and may have spawned in fresh water, much like today's salmon. There were turtles the size of a Volkswagen and penguin-like birds with teeth. In the skies were reptiles called pteranodons, one with a wingspread of 25 feet, but weighing only 25 pounds.
And then there were swimming reptiles. One, called an elasmosaur, was up to 45 feet long. Inside their gut were rounded stones, some as big as a softball, to help grind food. There were huge, fierce ocean-going lizards called mosasaurs, like the one on display at the entrance to KU's natural history museum. Mixed in with all these remains are a few, rare dinosaur fossils, probably ones who died near the ocean, floated out to sea, and sank.
In addition to the vertebrates there were oysters, squid, and a free-floating form of a starfish relative called a crinoid. The most common, easily collected fossil from these rocks is a clam called an inoceramid that grew to nearly 5 feet in diameter. Some of those clams hold fossilized pearls.
Mike Everhart has spent much of his life collecting, preparing, and studying these fossils. Reading this book, you might think spectacular fossils cover the ground, just waiting to be picked up. They're not. They're hard to find. It takes time and tenacity, the kind that belongs to Everhart and the colleagues he credits throughout the book.
Even so, mysteries remain. Were the marine lizards hot or cold blooded? Why were pteranodons flying over the middle of an ocean, so far from land? And, maybe most important, what happened at the end of the Cretaceous when many of these marine animals, like the dinosaurs, disappeared from the planet?
Oceans of Kansas is technical but accessible, a carefully written, well-illustrated beauty of a book. It's the book that this long, strange time in Kansas history so richly deserves.