Imatge de l'autor

Michael J. Everhart

Autor/a de Oceans of Kansas

4 obres 166 Membres 4 Ressenyes

Sobre l'autor

Michael J. Everhart is Adjunct Curator of Paleontology at the Sternberg Museum of Natural History, Fort Hays State University.

Inclou el nom: Michael Everhart

Crèdit de la imatge: Michael J. Everhart

Obres de Michael J. Everhart


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Data de naixement
museum curator



A little disappointing. The book’s subtitle is “A Natural History of the Western Interior Sea”, and that’s what I was expecting, but that’s not what it is. In fact, it’s not clear what it is: a history of fossil collecting in Kansas, or a detailed reference catalog of all the fossil species known from the Cretaceous Smoky Hill Chalk member of the Niobrara formation, or the author’s personal reminiscences of fossil collecting, or a discussion of the swimming and flying mechanics of Cretaceous marine reptiles and birds. It took me a while, but I think I’ve figured out what’s going on here: Dr. Michael Everhart runs a pretty decent web site, also called Oceans of Kansas; it looks like a lot of the material from the web site was simply dumped together to make the book without considering the media differences.

For a “natural history” book, I’d expect considerably more information on paleogeography, paleoclimatology, and paleoceanography. There’s only a little of that - you have to explain that there was, in fact, an ocean in Kansas - but no discussion of the implications: what kind of climate would you expect if the entire North American interior was under 600 feet of water? What would the ocean currents be like? Which way would the prevailing winds go? And so on.

To make things worse, there’s a map purporting to show North America in the Cretaceous. The physical features on this map - where there’s water, highlands, mountains, lowlands, etc. - are more or less correct but way more detailed than the data justifies. For example, the map shows a river delta entering the interior sea in what would now be western Montana, complete with distributary channels; while the general inference that there’s Cretaceous deltaic sediment there is correct, there’s no way something as small and transitory as an individual distributary should be shown on a map of this scale. What’s worse, the map shows modern latitude lines, not paleolatitude lines. Although the modern lines are undoubtedly useful for locating modern features, they give the wrong impression for reconstructing the Cretaceous climate and oceanography.

The geology is also given short shrift - there’s a generalized surficial geological map of Kansas, and that’s it - no explanation for the lay reader as to why the geological units discussed in the text imply various depositional environments, and no depiction of the outcrop area of the Smoky Hill chalk (where the majority of the Cretaceous marine fossils discussed in the text come from). And why do you need to show the limit of Kansan glaciation in a book devoted to the Cretaceous?

The bulk of the book is detailed faunal lists for the Cretaceous western interior, broken down by taxonomic grouping. I’m as enthusiastic about fossils as anybody, but I don’t really need to know the complete collecting history of every single Cretaceous fish species (for example) ever found in Kansas. It would be much better, in a supposedly “natural history” book, to discuss the sea life by trophic level, rather than a chapter on invertebrates followed by a chapter on fish followed by turtles followed by elasmosaurs, etc. Some of the material on the early fossil collectors, especially the infamous rivalry between Othniel Marsh and Edward Cope, is interesting but doesn’t really need to be discussed in such detail.

There’s some redemption when Dr. Everhart talks about the biomechanics of Cretaceous animals. How did elasmosaurs work, for example? The “popular” reconstructions have always depicted them as slow “rowing” swimmers with highly flexible snake-like necks that snatched fish out of the water from above; however, analysis of the vertebrae shows that the neck was not very flexible, center of gravity considerations preclude lifting the head a significant distance out of the water without destabilizing the body, the eyes and nostrils are near the top of the head (making it unlikely that the animal could see prey below it even if it did lift its head above the surface) and inspection of the limb skeleton suggests that the animal probably “flew” underwater, like a penguin, rather than rowing slowly along. Thus we’ve got a rapid swimmer with a fairly rigid neck - but why was the neck so long?

Pteranodons pose a similar mystery. Their bones are extremely fragile and very lightweight; a Pteranodon longiceps had a wingspan of more than 20 feet but probably weighed around 25 pounds - with a body about the size of a housecat. How did the muscles on such a lightly built creature work without pulling the animal’s own bones apart? How did it deal with any sort of air turbulence while flying - was there no wind shear in the Cretaceous? What was the purpose of the head crest, which has a highly variable morphology and grows to ridiculous size in some species?

Dr. Everhart is also interesting when discussing his own fossil-collecting exploits - explaining just how difficult it is to remove and transport and exquisitely fragile skeleton when you’re twenty miles from the nearest highway. However, I would have like to have seen some discussion of collecting sites. I can appreciate that you don’t want hordes of amateurs descending on western Kansas to dig out their very own mosasaur - especially after Dr. Everhart mentions an incident where someone looted a partially excavated specimen he was working on - but there’s so little information on fossil provenance that it’s sometimes hard to tell where in Kansas the collecting areas are. It also would have been nice to give a little more acknowledgment of the contributions of amateurs to paleontology, and a better description of how field collecting works. There’s also no discussion, except casual references in the text, of which museums an interested party could go to look at the fossils (this is especially surprising, since Dr. Everhart is a curator of the Sternberg Museum in Hays, Kansas; you’d expect him to pump his institution a little more).

Lastly, Dr. Everhart is not very satisfying when discussing the end of the Cretaceous. There’s the usual mention of “uplift” draining the seaway, but no explanation as to why North America was being uplifted right then. He also doesn’t buy the impact hypothesis for the KT extinction event, citing a “combination of factors” instead - without explaining what those factors might be. There’s a silly and naive analogy comparing the size of the of the Yucatan impact crater with a similar event inflicted by a BB sized particle on a hypothetical globe 66 inches in diameter (1 inch to 120 miles). Dr. Everhart states that the event would leave a crater 1 inch wide and 1/120th of an inch deep, and expresses his doubt that an event affecting 0.00005 percent of the planet’s surface could have such far-reaching effects. The flaw in the analogy, of course, is that on Dr. Everhart’s scale, the atmosphere is only 1/10th of an inch thick, and that’s all the impact has to affect – not the entire planet.

So I can close on a positive note - the book has a terrific bibliography and there’s some nice color plates with reconstructions of various Cretaceous marine creatures. All and all, however, not worth it unless you have a specialist interest; visit the web site instead.
… (més)
setnahkt | Hi ha 3 ressenyes més | Dec 16, 2017 |
In the prehistoric past the central section of the US was covered in a deep see leading to the Antarctic. This book outlines in both a scientific and a more readable manner the life which existed at the time. Overall if you are interested in paleantology of the US it is a good book to read.
dswaddell | Hi ha 3 ressenyes més | Sep 5, 2011 |
The particular value of this book is that Everhart gives you a complete survey of what is known about the habitat in question, before this lost sea was wiped out by long-term geological processes; the author's suspicion is that the notorious late-Cretaceous asteroid strike was merely the climax in that extinction event. Also useful is that Everhart gives you a history of paleontological work in the region, including the 19th-century "bone wars" of Edward Cope and Othniel Marsh.
Shrike58 | Hi ha 3 ressenyes més | Aug 3, 2009 |
A totally cool book about what "Kansas" was like before the comet hit 65 million years ago. Informative, interest-holding and eminently readable.
JNSelko | Hi ha 3 ressenyes més | Jan 17, 2009 |


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