The authors are grateful to all of the local residents who helped to make our study pleasant and successful. Several individuals became interested in the research and their enthusiasm was especially encouraging. Tom Kleeberg, Consulting Geologist, Graham, N.C., showed us several alteration centers and explained traditional prospecting methods for pyrophyllite and other common products of high-sulfidation alteration. Terry L. Klein, Terry W. Offield, and Robert E. Koeppen, U.S. Geological Survey, contributed to the early field reconnaissance and later field mapping. Elizabeth H. Hughes participated in an early stage of the project by field mapping in the central part of the project area and doing mineralogic studies (Hughes, 1987).

Substantial contributions to the field work and laboratory studies on the project were made by Spanish and United States members of two cooperative projects supported by the United States-Spain Joint Committee for Science and Technological Cooperation, the Instituto Tecnológico GeoMinero de España, the Servei Geológic de Catalunya, and the North Atlantic Treaty Organization (NATO) Collaborative Project No. 530/88.

To these supporting scientists of diverse disciplines and experience, Carmen Anton-Pacheco, Lawrence C. Rowan, Marguerite J. Kingston, Nancy Milton, Cathy M. Ager, and Andreu Bonet, we owe special thanks for technical advice, assistance in the field, and not least for their perseverance and good humor during many less-than-ideal days in the field.