I have just learned of the death of Jeff Wilson. The introduction below was given at a Clay Minerals Society Meeting held in Burlington VT in 2005, and highlights some of his outstanding career. Introduction of Dr. Jeff Wilson, Bailey Award Winner The Marilyn and Sturges W. Bailey Distinguished Member Award is the highest award of The Clay Minerals Society, and is given for outstanding scientific research in clay science. This year we have a very distinguished and deserving winner, Dr. M. J. Wilson, who has made the trip across the Pond to be with us, and by pond I don’t mean Lake Champlain. Jeff comes from a little country north of England that invented the modern world. Before his official retirement in 1997, Jeff was Head of the Division of Soils and Soil Microbiology at the Macaulay Institute in Aberdeen, Scotland, where he is now an Honorary Research Fellow. Jeff has 40 years of experience in research on the chemistry and mineralogy of soils, from both agricultural and environmental points of view. He has published over 180 papers and compiled and edited four books in these areas. In 1990 he was awarded the first Schlumberger Medal, which is the highest award of the Mineralogical Society, for excellence in mineralogical research and its applications. In 2003 he gave the 4th George Brown Lecture to the Mineralogical Society. He taught soil mineralogy for over 10 years at the University of Aberdeen, also taught at the University of Naples, and is an honorary professor at Zhejiang Agricultural University in Hangszhou, China. In 1985 he was elected to the Royal Society of Edinburgh. In characterizing Jeff’s science in a few words, one would point to careful experimental work, unhurried and thoughtful scholarship, a high degree of originality, a large variety of topics investigated, and a clear presentation of results. He has published papers on topics that are very relevant to society’s problems, such as his work on soil susceptibility to acid rain, and on the sustainability of agriculture in the Red Soils of China. He also has studied minutiae, such as the occurrence of thaumansite in weathered furnace slag found near his boyhood home in Wales. He has investigated these seemingly disparate topics with equal zest. In reading his papers one can feel the fun he must experience in science, and this joy is contagious. Jeff has been involved in many pioneering studies, and often has been ahead of his time. For example, in the 1970’s he documented the formation of a smectite-like mineral in hornblende from the weathering of discrete, lamellar, iron-rich intergrowths. This observation was years before Banfield’s excellent imaging of such intergrowths. About this time he also found that the weathering of feldspars occurred at dislocations and in etch pits, which was inconsistent with the then accepted model based on the formation of a residual layer, a model that required that all parts of the mineral grain are attacked at equal rates. This discovery was a precursor to the work of Berner that followed. Now biological weathering is very much in vogue, but Jeff was investigating this topic in the early 1980’s with research on the weathering of serpentines and basalts by lichen, with the formation of oxalate minerals. Jeff also described and characterized some new and unusual minerals. One of these is called macaulayite, a long-spacing, swelling, iron-rich mineral that he named after his institution. It has a layer structure and is thought to consist of a double hematite unit terminated on both sides by silicate sheets, with water molecules between these sheets. It swells to about 34 Å. As I heard the story, one of his colleagues at the Macaulay had passed away. As a good scientist should, this colleague kept notes that were coherent enough that someone could understand them after his death. Jeff read through these notes, and found reference to an unusual mineral formed from the deep weathering of granite. Jeff and his colleagues later were able to isolate macaulayite using a magnetic separator of their own invention. In my opinion, Jeff’s most significant clay discovery, with McHardy and Tait, was that of interparticle diffraction for illites in sandstones from a North Sea oil field. In this paper, Jeff and his colleagues demonstrated the need to use critical point drying to preserve *in situ* clay textures for SEM study, and they applied Pt-shadowing to measure illite particle thicknesses. In trying to justify their TEM measurements of illite crystals having thicknesses of 2 to 3 nm with the XRD data which showed much thicker, 20% expandable, R1 ordered illite/smectite crystals, they realized that it was the interacting surfaces of the thin illite crystals in the sample that formed the smectite layers in the illite/smectite. Illite/smectite was simply composed of stacks of thin illite crystals that had water adsorbed on their basal surfaces. Later Paul Nadeau recognized the overall importance of interparticle diffraction to understanding mixed-layer clays, and Paul further investigated and developed the concept. I have been able to mention only some of Jeff’s accomplishments as a researcher, but he also was an effective administrator. I visited the Macaulay Institute in 1982, on the day that Jeff was made Head of Mineralogy, after Mackenzie retired. The Macaulay board in charge of picking the next Head interviewed about 4 candidates in the morning, Jeff was appointed Head in the afternoon, and that was that. No nonsense from the board. Later Jeff was able to help save the institute, when Thatcher tried to shut it down, by instigating an international letter writing campaign. Ladies and Gentlemen The Clay Mineral Society is greatly honored to bestow the Bailey Distinguished Member Award on Jeff Wilson, and we are, in return, greatly honored by his presence at our annual meeting. -- Dennis Eberl Boulder, CO, USA Todos Santos, Baja Sur, Mexico -- Dennis Eberl Boulder, CO, USA Todos Santos, Baja Sur, Mexico