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Geology of Iowa: Over two billion years of change
150 unduly alarmist. Thirdly, it explores not only the present and likely future scenarios, but also directs attention to the ways and means n o w available of avoiding them by placing the CO 2 impact on climate within the wider framework of world-wide energy and land-use policies. It places the eventual COs-induced climatic change within the framework of all other anthropogenic climate factors. It also analyses the possible socio-economic repercussion of climatic change, and last but not least points towards the ways of avoiding the C O 2 / c l i m a t e problem. The bibliography is very complete up to the end of 1981; a number of clear annexes present some explanations together with some technically more involved topics, excellent and thorough author and subject indices plus a glossary are also provided. M. Benarie, Bretigny-sur-Orge Jack C. Troeger, 1983. From Rift To Drift: Iowa's Story in Stone. Iowa State University Press, Ames, x + 152 pp., U.S.$14.95 (hard cover).
From Rift To Drift was written for rockhounds and other non-geologists w h o want to learn about the geologic history of Iowa. Troeger relies on anologies that relate geologic phenomena to commonplace objects and processes to c o n v e y geologic history and processes to the reader. For example, the layer-cake analogy is used repeatedly as an aid in discussing various aspects of Iowa stratigraphy. Comparing Iowa's glacial drift to icing on the layer cake may be corny but effective. Perhaps the strongest point of this book is that Troeger treats geology as a series of exciting adventures, thus stimulating interest in the subject rather than burdening the novice with a flood of facts and technical terms. The first portion of Troeger's book is devoted to presenting a minicourse in geology. Due to the scope and focus of the book, many simplifications are used in places where more explanations are needed. The following statement serves as an example of one of these oversimplifications: " B y comparing widely separated rock layers that contain similar fossils, geologists can locate the buried resources that our busy society de-
mands." (p. 9). Although biostratigraphy is usually an integral part of any search for strata-bound petroleum and mineral resources, it usually constitutes a small portion of the effort that explorationists must spend in successful searches. In addition, several incorrect statements are made, such as equating, "strike-slip" with " t r a n s f o r m " faults (p. 19, fig. 2.4) when transform faults are special types of strike-slip faults. He also states that Jurassic rocks are rare in the United States (p. 105). The latter statement is certainly true of the Midcontinent region, but much of the western United States and the Gulf Coast region are underlain by thick Jurassic deposits that form spectacular outcrops in the West, and are important petroleum reservoirs in the Gulf Coast (e.g., Smackover Formation) as well as in the western overthrust belt (e.g., Nugget and Twin Creek formations). The second half of From Rift to Drift tells the story of Iowa's geological history using the concepts developed earlier. Troeger illustrates the variety of geology found within the state along with the variety of explanations that have been used to account for geologic features. His story is punctuated with humor, often corny, but usually to drive home a point. Some of this humor is in the form of cartoons, some by way of puns, and some through literature quotes from Mark Twain. If Troeger's lectures are delivered in a similar manner, then the students in the Ames, Iowa, school system have a treat awaiting them when they take his classes. Despite oversimplifications and some inaccurate statements. I found this book very enjoyable to read. I would not recommend it as a textbook, but I do believe that it would make an excellent gift for a y o u n g or novice rockbound whether he or she lives in Iowa or elsewhere. For the more serious rockhounds and students of midcontinent geology, I think that Anderson's Geology of Iowa which is also published by the Iowa State University Press, is a better buy. R.L. Brenner, Iowa City, Iowa Wayne I. Anderson, 1983. Geology o f Iowa: Over Two Billion Years of Change. Iowa State University Press, Ames, viii + 268 pp., U.S.$32.50 (hardback), $17.95 (paperback).
151 Geology of Iowa by Wayne I. Anderson was written for beginning college students, school teachers, and others that have an interest and some background in geology or earth science. Without some geologic back-
haps this mixing of Recent history with ancient history makes for more interesting reading for the layman, but it appears to be the result of poor organization to me. Another feature that I found to be frustrating is the
ground, the reader may have trouble coping
lack of preciseness in locating features pic-
with geologic terms, since this book lacks a
tured in figures, thus making it difficult or
glossary. Anderson's book is divided into eleven chapters. The first chapter summarizes the geologic setting within which the State of Iowa is located, and introduces the
impossible to find where some specimens could be collected or outcrops could be
reader to the geologic time scale. The next nine chapters are devoted to Iowa's geologic history with a chapter each for the Pre-
end of each chapter will greatly aid students and professionals who contemplate working
cambrian, the first six periods of the Paleozoic, the Mesozoic Era, and the Cenozoic Era. Chapter eleven is entitled "Geology and M a n " and deals with Iowa's natural resources with an emphasis on water, its most important resource. In general, Geology of Ioawa is well written and nicely illustrated. Rocks and fossils are lucidly discussed and illustrated with field and specimen photographs and very effective line diagrams. There are three pages of color photographs that are well done, but are not necessary other than to show outsiders that Iowa is a colorful place at times. On the other hand, color renditions of the bedrock geologic map of Iowa and of the hydrogeologic map of Iowa are much more effective than the monochromatic versions published elsewhere. Although most of the black and white photographs are good, several lack sharpness or are washed out and probably would have been rejected as illustrations in most journals. I found Geology of Iowa to be easy to read and informative. However, there are several aspects of this book that I found annoying. Some sections appear to be misplaced. For example, I do not think that glacial erratics and meteorites should be discussed in the chapter dealing with the Precambrian. Although these materials were derived from terrestrial and extra-terrestrial sources that were undoubtedly Precambrian in age, they were emplaced during the Cenozoic and should have been discussed in that context. Likewise, Anderson discusses Julien Dubuque and his mining exploits in the Ordovician chapter under the section heading "Galena Formation", rather than in the " G e o l o g y and Man" chapter. Per-
visited. The extensive lists of references at the
in Iowa. These references include unpublished master of science theses and doctoral dissertations, some of which are available only from university libraries. I recommend this book to persons interested in the geology of the North American midcontinent who have at least some knowledge of geologic principles. R.L. Brenner, Iowa City, Iowa
Hallam, 1983. Great Geological Controversies. Oxford University Press, vii + 182
A.
pp., Lstg.15.00 (hardback)/.£stg.7.95 (softcover). This slender volume deals with five celebrated corltroversies that profoundly affected the history of geology. The author's objectives are to review some significant turning points in the evolution of geological thought, to evaluate how these changes came about, and thereby to comprehend the ways in which scientific concepts develop, are tested, and become modified. T w o of the five c o n t r o v e r s i e s - - o n e between neptunists, volcanists, and plutonists and one between catastrophists and uniformitarians--took place during the "heroic age of geology" (approximately 1775-1850), when developing knowledge of the earth profoundly affected Western philosophy as well as scientific thought. The reader is presented with a familiar cast of characters (including Werner, Desmarest, Hutton, Playfair, Cuvier, and Lyell) and with events that have been recounted at length in classic histories of geology (Geikie, 1905; Adams, 1938) and in many introductory texts. Once again, we meet James Hufton ( 1 7 2 6 - 1 7 9 7 ) , " . . . t h e vivacity
From Rift To Drift was written for rockhounds and other non-geologists w h o want to learn about the geologic history of Iowa. Troeger relies on anologies that relate geologic phenomena to commonplace objects and processes to c o n v e y geologic history and processes to the reader. For example, the layer-cake analogy is used repeatedly as an aid in discussing various aspects of Iowa stratigraphy. Comparing Iowa's glacial drift to icing on the layer cake may be corny but effective. Perhaps the strongest point of this book is that Troeger treats geology as a series of exciting adventures, thus stimulating interest in the subject rather than burdening the novice with a flood of facts and technical terms. The first portion of Troeger's book is devoted to presenting a minicourse in geology. Due to the scope and focus of the book, many simplifications are used in places where more explanations are needed. The following statement serves as an example of one of these oversimplifications: " B y comparing widely separated rock layers that contain similar fossils, geologists can locate the buried resources that our busy society de-
mands." (p. 9). Although biostratigraphy is usually an integral part of any search for strata-bound petroleum and mineral resources, it usually constitutes a small portion of the effort that explorationists must spend in successful searches. In addition, several incorrect statements are made, such as equating, "strike-slip" with " t r a n s f o r m " faults (p. 19, fig. 2.4) when transform faults are special types of strike-slip faults. He also states that Jurassic rocks are rare in the United States (p. 105). The latter statement is certainly true of the Midcontinent region, but much of the western United States and the Gulf Coast region are underlain by thick Jurassic deposits that form spectacular outcrops in the West, and are important petroleum reservoirs in the Gulf Coast (e.g., Smackover Formation) as well as in the western overthrust belt (e.g., Nugget and Twin Creek formations). The second half of From Rift to Drift tells the story of Iowa's geological history using the concepts developed earlier. Troeger illustrates the variety of geology found within the state along with the variety of explanations that have been used to account for geologic features. His story is punctuated with humor, often corny, but usually to drive home a point. Some of this humor is in the form of cartoons, some by way of puns, and some through literature quotes from Mark Twain. If Troeger's lectures are delivered in a similar manner, then the students in the Ames, Iowa, school system have a treat awaiting them when they take his classes. Despite oversimplifications and some inaccurate statements. I found this book very enjoyable to read. I would not recommend it as a textbook, but I do believe that it would make an excellent gift for a y o u n g or novice rockbound whether he or she lives in Iowa or elsewhere. For the more serious rockhounds and students of midcontinent geology, I think that Anderson's Geology of Iowa which is also published by the Iowa State University Press, is a better buy. R.L. Brenner, Iowa City, Iowa Wayne I. Anderson, 1983. Geology o f Iowa: Over Two Billion Years of Change. Iowa State University Press, Ames, viii + 268 pp., U.S.$32.50 (hardback), $17.95 (paperback).
151 Geology of Iowa by Wayne I. Anderson was written for beginning college students, school teachers, and others that have an interest and some background in geology or earth science. Without some geologic back-
haps this mixing of Recent history with ancient history makes for more interesting reading for the layman, but it appears to be the result of poor organization to me. Another feature that I found to be frustrating is the
ground, the reader may have trouble coping
lack of preciseness in locating features pic-
with geologic terms, since this book lacks a
tured in figures, thus making it difficult or
glossary. Anderson's book is divided into eleven chapters. The first chapter summarizes the geologic setting within which the State of Iowa is located, and introduces the
impossible to find where some specimens could be collected or outcrops could be
reader to the geologic time scale. The next nine chapters are devoted to Iowa's geologic history with a chapter each for the Pre-
end of each chapter will greatly aid students and professionals who contemplate working
cambrian, the first six periods of the Paleozoic, the Mesozoic Era, and the Cenozoic Era. Chapter eleven is entitled "Geology and M a n " and deals with Iowa's natural resources with an emphasis on water, its most important resource. In general, Geology of Ioawa is well written and nicely illustrated. Rocks and fossils are lucidly discussed and illustrated with field and specimen photographs and very effective line diagrams. There are three pages of color photographs that are well done, but are not necessary other than to show outsiders that Iowa is a colorful place at times. On the other hand, color renditions of the bedrock geologic map of Iowa and of the hydrogeologic map of Iowa are much more effective than the monochromatic versions published elsewhere. Although most of the black and white photographs are good, several lack sharpness or are washed out and probably would have been rejected as illustrations in most journals. I found Geology of Iowa to be easy to read and informative. However, there are several aspects of this book that I found annoying. Some sections appear to be misplaced. For example, I do not think that glacial erratics and meteorites should be discussed in the chapter dealing with the Precambrian. Although these materials were derived from terrestrial and extra-terrestrial sources that were undoubtedly Precambrian in age, they were emplaced during the Cenozoic and should have been discussed in that context. Likewise, Anderson discusses Julien Dubuque and his mining exploits in the Ordovician chapter under the section heading "Galena Formation", rather than in the " G e o l o g y and Man" chapter. Per-
visited. The extensive lists of references at the
in Iowa. These references include unpublished master of science theses and doctoral dissertations, some of which are available only from university libraries. I recommend this book to persons interested in the geology of the North American midcontinent who have at least some knowledge of geologic principles. R.L. Brenner, Iowa City, Iowa
Hallam, 1983. Great Geological Controversies. Oxford University Press, vii + 182
A.
pp., Lstg.15.00 (hardback)/.£stg.7.95 (softcover). This slender volume deals with five celebrated corltroversies that profoundly affected the history of geology. The author's objectives are to review some significant turning points in the evolution of geological thought, to evaluate how these changes came about, and thereby to comprehend the ways in which scientific concepts develop, are tested, and become modified. T w o of the five c o n t r o v e r s i e s - - o n e between neptunists, volcanists, and plutonists and one between catastrophists and uniformitarians--took place during the "heroic age of geology" (approximately 1775-1850), when developing knowledge of the earth profoundly affected Western philosophy as well as scientific thought. The reader is presented with a familiar cast of characters (including Werner, Desmarest, Hutton, Playfair, Cuvier, and Lyell) and with events that have been recounted at length in classic histories of geology (Geikie, 1905; Adams, 1938) and in many introductory texts. Once again, we meet James Hufton ( 1 7 2 6 - 1 7 9 7 ) , " . . . t h e vivacity