Sedimentary Geology, 70 (1991) 83-84 83 Elsevier Science Publishers B.V., Amsterdam

Book Reviews

The Macmillan Field Guide to Geological Struc-

tures. John L. Roberts. Macmillan Press,

London, 1989, 250 pp., £stg. 12.95.

This book by John Roberts on geological struc- tures is written for the amateur geologist, and like

many books on natural history for a general read- ership, it is full of clear colour photographs, sim- ple diagrams and a very readable text. The book is

of a small size (20 X 14 cm), so that it is easy to

carry around in an anorak pocket or backpack for use in the field. The book contains more than 260 colour photos, mostly arranged in threes on every

right-hand page, with a caption to each giving a simple description. On the opposite page, the

structures are described in more detail with infor-

mation on how they are formed and their geologi- cal significance.

The book is divided into six parts: I, Sedimen-

tary Rocks; II, Igneous and Metamorphic Rocks; III , Unconformities and the Geological Record; IV, Mountain-Building and the Tectonic Record;

V, Structural Relationships in Folded Rocks; and

VI, Basement Rocks. Most sections begin with a few pages of introduction before the descriptions

and figures of the specific structures. All the com- mon structures that an amateur geologist is likely to come across, are illustrated and concisely ex-

plained. The photos are excellent. All are well chosen examples, with many coming from Britain, especially Scotland (naturally so since John Ro- berts is Scottish and has researched there for

many years). However, there is a good coverage of other countries too in the location of the pictures.

A feature of most of the photos is that there is no

geological hammer for scale. There was a time when the use of coins, camera lens caps, bananas,

fingers (etc.) for scale was frowned upon, but nowadays many geologists do not carry a hammer, being conservation-minded and wanting to pre- serve the outcrops for future generations.

Most of the geological structures in this book are naturally on the metre-scale; those you would see at an exposure from a distance of a few metres

or closer. The larger-scale structures of rocks, par-

ticularly those in the sedimentary rocks, are not covered: features like clinoforms, downlap surfaces and onlaps, which are best seen in large cliff

exposures. Such relationships between sedimen-

tary units form the basis of sequence stratigraphy, which is all the rage at the moment. But it will be some years before the amateur geologist is looking

for maximum flooding surfaces and lowstand

wedges. Hopefully, however, the keen amateur will want to go beyond knowing what structure he / she

is looking at, to putting it into the regional con- text, the facies model and palaeogeography (easier

concepts than sequence stratigraphy!), or the larger-scale tectonic picture. John Roberts is a

field-based, structural geologist, and he does give helpful comments on the use of the various struc-

tures in geological mapping and a short appendix with guidelines for structural fieldwork.

I do hope that this book is successful. It will

doubtless be available in most high-street shops

and so should get plenty of exposure. On the whole, the general public is fairly ignorant of

geology, although it is becoming more aware of some aspects nowadays, with the emphasis on

environmental issues such as global warming. This

is a most attractive book (and cheap). The text is very understandable. It is not full of jargon and long words, and a glossary is provided to help out here. It should make the man in the street more aware of what can be seen in rock outcrops. The

tourist should take a copy on his holiday, along

with the companion books on birds and wild

flowers, so that he can appreciate the natural environment much more. He may than be tempted

to attend some evening classes to get more of a

background, or to read some other geology books. The book will also be useful for undergraduate students who are doing their mapping projects. John Roberts is to be congratulated on producing such an attractive and readable book.

MAURICE TUCKER (Durham)

0037-0738/91/$03.50 © 1991 - Elsevier Science Publishers B.V.