Schiffer Publishing is pleased to bring out this entirely new edition of H.L. James classic study of the Navajo rug and the trading posts associated with each unique style. New information and an entirely different design help explain and display the beauty and craft of the Navajo Indians. Illustrated with 106 color images, many black-and-white photographs and drawings, and up-to-date price information, Post and Rugs traces the history of the Navajo rug and the impact the trading posts have had on its regionalization. There is also much background material on the Navajo people and their art.\nHere are design drawings showing elements characteristic of different weaving centers, superb color photographs of rugs typical of these centers, and detailed maps to the areas. Exquisite line drawings accompany the text showing all the steps in rug weaving, from the sheep to the finished rug. Also there is helpful advice on buying Navajo rugs and caring for them.

Acoma, the sky city of New Mexico, is presented here by an enchanting text and beautiful color photographs in this revised edition of the Southwest classic book. Occupied by the Acoma Indians, Acoma mesa pueblo is located 65 miles west of Albuquerque. This gem of antiquity is said to be the oldest continuously-inhabited community on the North American continent. The fascinating introduction was written by Frank Waters, one of New Mexico's most famous sons, a literary giant, and an authority on the history of the Indians of New Mexico. In Acoma, the buildings, the people, their traditions and their unique style of pottery are so closely related to this singular terrain that they have become known far beyond its desert.

will probably be clarified by the continued cooperative efforts of scientists such as those in the group that met in Berlin last September. The staff of Dahlem Konferenzen is responsible for making the meeting of this group memorably pleasant and pleasantly mem- orable. Dr. Bernhard's gifts of charm, organizational skill, and administrative toughness assured that the conference was run elegantly, smoothly, and decisively, even down to the choice of editors for this volume. Marie Cervantes-Waldmann performed minor miracles extracting manuscripts gently but persistently from the authors and in turning the typescripts into a book. The other staff members of Dahlem Konferenzen were unfailingly helpful even under trying circumstances. They will be well rememberedbyall who were fortunate enough to be asked to Berlin for the first week in September, 1980. Mineral Deposits and the Evolution of the Biosphere, eds. H. D. Holland and M. Schidlowski, pp. 5-30. Dahlem Konferenzen, 1982. Berl in, Heidelberg, New York: Springer-Verlag. Microbial Processes in the Sulfur Cycle Through Time H. G. TrUper Institut f. Microbiologie, Rheinische Friedrich-Wilhelms-Universitat, 5300 Bonn 1, F. R. Germany Abstract. Two microbial processes are involved in the sulfur cycle of the earth's biosphere: anoxic dissimilatory sulfur oxidation by phototrophic bacteria and dissimilatory sulfate reduction by sulfate-reducing bacteria. In the presence of oxygen at chemoclines and redoxclines dissimilatory sulfur oxidation by chemolithotrophic bacteria (Thiobacillus, Beg- giatoa, and others) occurs. In addition, dissimilatory sulfur reducing bacteria participate in the sulfur cycle.

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.