Geology Underfoot in Southern California by Robert P. Sharp and Allen F. Glazner describes twenty geological features which are located in southern California. Wave action, volcanoes, and geological faults are all discussed with examples that are found in the southern half of the state. Although the areas described extend somewhat farther north than what most people would generally regard as "southern" California, the stories are well written and informative. Unfortunately, the physical quality of the book is somewhat lower than I would like for a reference or guide book.
As I have said on at least one prior occasion, it is generally easy to interest young people in the earth sciences since theory and practice meet in such concrete and obvious ways. Geology Underfoot is a good way to start this process. The book is much less formal than some of the other standards in the field, the Sinkankas books for example. However, it has just enough information to explain each feature with pictures, one or more maps, and a good description of the geology related to the site.
More than half of the sites described in the book are within a three to four hour drive from Fallbrook; thus, many of the trips can be accomplished in a day. In addition, many of the locations are clustered together so that it would not be difficult to organize a geology field trip based on the material in the book. Only a few of the trips seem to require a four-wheel drive vehicle, although no clear mention of this is included in the text or in the directions to the sites.
Despite the worthwhile content of the book, there are several reasons why Geology Underfoot was a slight disappointment to me. First, the contrast of about one third of the pictures is too low. As a result, the pictures appear to be hazy or dim. The pictures on pages 155 and 157 illustrate the difference between pictures with poor and good contrast. The picture on the upper portion of page 185 is probably the worst picture in the book -- about half of the picture is simply too light to make anything out. Second, some of the pictures show an open or closed pocket knife or a key chain to establish scale. A six-inch ruler would have been considerably more appropriate. Third, there is a distracting lack of consistency in the design and rendering of the maps and charts. None of these are serious problems by themselves, but the number of places where details are ignored detracts from the overall quality of the book.
I hope that the publisher keeps the book up to date. Although Geology Underfoot was published in 1993, there is at least one new geological feature that absolutely must be included in future editions. About 15 miles east of State Highway 247 on Bessemer Mine Road (on BLM land) you can walk along a portion of the fault that breached the ground in June 1992, during the magnitude 7.6 Landers earthquake. In spots, the vertical displacement of the fault scarp is in excess of six feet. The horizontal displacement was measured as ten to twelve feet. Quite spectacular -- but that's southern California!
Even with the production shortcomings of Geology Underfoot, I am still a fan of Mountain Press' budget-priced products and I believe that this book is a good investment. I doubt that anyone will be able to visit any of the sites described in Geology Underfoot without learning how to see the world through new eyes. What better way is there to spend a bright spring day than on a journey of exploration and discovery? Try it you'll like it.
Geology Underfoot in Southern California by Robert
P. Sharp and Allen F. Glazner; Mountain Press Publishing
Company; ISBN 0-87842-289-7; $12.00.
Copyright © 1994 by Fallbrook Gem and Mineral Society, Inc.
The preceding article was originally published in the March 1994 issue of Lithosphere, the official bulletin of the Fallbrook [California] Gem and Mineral Society, Inc; Richard Busch (Editor).
Permission to reproduce and distribute this material, in
whole or in part, for non-commercial purposes, is hereby granted
provided the sense or meaning of the material is not changed and
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Last updated: 18 September 2002