Macdougall, J. D., 1996

This is a great little book. It arrived in my mail a year ago, and I failed to read it as promptly as I now wish I had. The cover bears a statement from Publishers Weekly claiming that the book is "A splendid introduction for the lay reader". I would modify that to read "...for anyone". I consider myself to be a seasoned professional geologist by now, having taught physical and historical geology for nearly twenty years. Still, I found this book to be very engaging. I actually substituted it for the fiction that I oftentimes read in the evenings because A Short History of Planet Earth reads like something new and fresh. It will certainly appear on my adoption list, particularly for courses that we teach for earth science teachers.

The book's attractiveness comes from Macdougall's ability to write as though he were speaking to the reader. This conversational style leads one to the inevitable conclusion that "This is really pretty neat stuff!" The content covers the whole spectrum of Earth's history and is styled after such historical geology texts as Wicander and Monroe's Historical Geology or Dott and Prothero's Evolution of the Earth. Macdougall actually borrows an illustration or two from the latter, but he carefully avoids mimicking it. There is a review of the history of geological thought (Chapter 1, "Reading the Rocks"), and then a sequence of chapters that treat everything from Precambrian history (Chapter 2, "Early Days") to a philosophical discussion of what is likely to happen on Earth now that humans and the Great Ice Age have had their opportunities to shape its surface (Chapter 13, "What Comes Next? Geology and Man"). The author even nods in the direction of palynology on a couple of occasions, and gives fossil pollen and spores recognition as significant tools in understanding the K-T extinctions and Pleistocene climate changes.

Three chapters seemed to me to be especially good. Chapter 2, "Early Days", provides an unusually clear discussion of radiometric dating, and, particularly, the significance of zircons in determining the age and location of the first fragments of continental crust. I wonder at these refractory little white grains whenever I see them in concentrations of Georgia's beaches. They have many stories to tell, and are too often overlooked by geologists. In Chapter 3, "Wonderful Life", Macdougall seriously questions the validity of the Miller-Urey experiment, stating that "In a carbon dioxide-rich atmosphere, the Miller-Urey electrical discharge method for creating amino acids doesn't work". I don't know how many times I have faithfully taught my students that the famous amino acid experiment successfully models the early planet, but apparently I need to learn more about this. Finally, Chapter 9, "From Pangea to (Almost) the Modern World: The Mesozoic Era", includes a very interesting and well-explained history of accretion in western North America during the Mesozoic, and a clear description of what geological signatures accompany rifting (salt beds, volcanic deposits, conglomerates, etc.)

I found only a few errors in this otherwise excellent book. In Chapter 9, for example, Tyrannosaurus is referred to as the Jurassic "king of the beasts"; doubtless even Macdougall has been adversely affected by the hyperbole associated with Jurassic Park.

Macdougall won me as a disciple as I read Chapter 12, "The Great Ice Age". There the author describes climate modelling and then observes that "Ultimately, information from the earth itself, the record in the rocks reflecting the actual climate changes that occurred, is the standard against which these theoretical treatments must be judged". Models are only models; they are not truth. The only true history lies within the Earth itself, and J. D. Macdougall does a mighty good job of describing it.