Inadequate observation of sedimentary TRUSHKovA and KUKHARENKO'S "Atlas of structures has been responsible for incorrect Placer Minerals." The most comprehensive interpretation of the order of superposition atlas is the "Atlas of Textures and Struc in deformed beds and this has led, in turn, tures of Sedimentary Rocks" edited by A. to gross errors in stratigraphy and structure. V. KHABAKOV (1962). Failure to recognize and utilize those Our Atlas is an outgrowth of our work on structures which indicate direction of cur "Paleocurrents and Basin Analysis," a book rent flow has also led to incorrect, or at in which directional sedimentary structures least incomplete, understanding of basin are described and interpreted with special development. reference to the evolution of sedimentary We believe, therefore, that there is need for basins. That work, however, contains mini a work which constitutes a field guide to the mal photographic material - just enough study of these structures - a book in to give the reader some concept of the sedi which these structures, so difficult to mentary structures described."

The study of paleocurrents, since 1963, is now a very routine part of sedimentology, and more and more such studies are finding use in other fields. Thus it seemed appropriate for us to review post-1963 developments and present them in a compact manner for the interested reader. Instead of rewriting a second edition, which thirteen years later we would organize in a completely dif ferent way, we have brought each chapter up to date with new material up to 1976. A new update supplement has in this edition been inserted after each one of the original chapters. We have stayed close to the original theme of paleocurrents-how to measure them and how to use them to solve geological problems ranging in scale from the hand specimen to the sedimentary basin and beyond. We have used many annotated references and tables to help pre sent this information to the reader. The reader will note that we have cited a few 1962 references - pUblications that appeared too late to be cited in the original 1963 edition. A few times we have also cited a reference which was included in the first edition. These are marked with an asterisk and hence do not appear in the new lists of references. We have been aided by many. In Cincinnati, WANDA OSBORNE and JEAN CARROL did typing and RICHARD SPOHN, the University's geological librarian, was very helpful in obtaining many references to the literature."

The first edition appeared fourteen years ago. Since then there have been significant advances in our science that warrant an updating and revision of Sand and Sandstone. The main framework of the first edition has been retained so that the reader can begin with the mineralogy and textural properties of sands and sandstones, progress through their organization and classification and their study as a body of rock, to consideration of their origin-prove nance, transportation, deposition, and lithification-and finally to their place in the stratigraphic column and the basin. The last decade has seen the rise of facies analysis based on a closer look at the stratigraphic record and the recognition of characteristic bed ding sequences that are the signatures of some geologic process-such as a prograding shallow-water delta or the migration of a point bar on an alluvial floodplain. The environment of sand deposition is more closely determined by its place in such depositional systems than by criteria based on textural characteristics-the "fingerprint" approach. Our revi sion reflects this change in thinking. As in the geological sciences as a whole, the concept of plate tectonics has required a rethinking of our older ideas about the origin and accumu lation of sediments-especially the nature of the sedimentary basins."

The United States Geological Survey (USGS) is a scientific organization created in 1879, and is part of the U.S. government. Their scientists explore our environment and ecosystems, to determine the natural dangers we are facing. The agency has over 10,000 employees that collect, monitor, and analyze data so that they have a better understanding of our problems. The USGS is dedicated to provide reliable, investigated information to enhance and protect our quality of life. This is one of their circulars.

With A Section On Geology And Quarrying, Warm Spring Ridge, West Virginia.