Edward Hitchcock (1793–1864)

A lot has been learned since the author penned this book. The principle of uniformitarianism seems to be in place. It seems understood that younger beds are deposited on older beds. Some classifications seem foriegn such as "Aqueous and Igneous" which of course later evolved into sedimentary and igneous with the addition of metamorphic sometime later. One of five sections in the book deals with geology and religion, at topic not given this much prominence in current geology texts.

The five sections of the book are, in order, "Description and Dynamic Geology", "Paleontology", Bearings of Geology upon Religion", "Economic Geology", and "North American Geology" Because the book was written befor continental drift was suspected, there was not yet a realization that European geologic history closely matched North American and that might explain partially why North America is given a sepereate isolated part of the book.

In browsing the book, there are a lot of names and classifications that are not in use today. Cenozoic time is referred to as Cainozoic, a spelling difference mainly. Concretins were not understood and were classified by shape. Pennsylvanian age was Carboniferous and Cambrian was Huronian age. A few other unfamiliar terns are Interzoic and Hypozoic. Mesozoic is referred to as the "Secondary" period, aparently later named while the Tertiary and Quaternary were not renamed. Quaternary is sometimes referred to as the Diluvian.

Mineralogy was hurt by the non-existence of microscopes and is pretty short. There are so many unrecognized names for rocks and and ages the text is hard to follow.

Glacial processes are adequately described although at publishing time no North American glaciers were known to the author so he referrs to European, Greenland and asian glaciers.

There was little known at that time about the interior of the earth. The author mentions a crust but there was no common knowledge of its thickness or what lay below. The author speculates the earth is shrinking as its interior cools.

The section on paleontology is similarly best thought of as evolving at that time. There is a section on speculation of how fossils form termed "The Theory of Petrification" which indicates that solution and dissolution of minerals was not at all understood. It was known that the geologic eras ended with what the author calls catastrohpes, in which most of the living things became extinct. There was not yet a belief that species changed or evolved over time.

Ther are few maps in the book. On page 408-409, there is a geologic outcrop map for North America. At that scale, the rocks are split mostly just into igneous, metamorphic and sedimentary, but with some differences. Sedimentary rocks are split between those having numerous fossils, and those that do not. There is an additional class of rock called "beds of coal" that covers vast portions of the continent, mostly all of Appalachia and what looks lke the midwest around Illinois. There is an 11 page index.

The hardback covers, both front and back are elaborately embossed.

For those who have made geology a profession, this book is very interesting.… (més)