A good number of friends and colleagues have contributed to the completion of this study. Andrew Wallace of the History Department at Northern Arizona University has generously shared his copies of Whipple's diary and other materials and also read and commented on early chapters. Sidney Ash, of Weber State University, took time from his research at Petrified Forest to discuss aspects of the park's geology and to guide me to several sites, including, perhaps, John Muir's" Sigillaria Grove." Similarly, David Wilcox of the Museum of Northern Arizona shared his knowledge of the archaeology of Petrified Forest, and Dale Nations of the Geology Department at Northern Arizona University was a helpful and encouraging colleague. Personnel at Petrified Forest invariably were generous with their time and made research trips to the park library a pleasant undertaking. In particular, I wish to thank Superintendents Michele M. Hellickson, Gary Cummins, and Edward Gastellum as well as District Ranger Terry Maze. The National Park Service Western Regional Historian, Gordon Chappell, was a good source of information, and I thank him for his support. Sarah J. Hillyer, the NAU History Department's efficient administrative assistant, not only proofread chapters but, more important, provided expert guidance through the mysteries of word processing.
Northern Arizona University provided organized research grants that facilitated research at the Huntington Library, the National Archives, and the Hayden Library at Arizona State University, and the staffs at those institutions expedited research tremendously. Karen Underhill and Laine Sutherland at Archives and SpeCial Collections at Northern Arizona University's Cline Library were invariably helpful, and documents librarian Sean Evans guided me to much material that I otherwise would have missed. Susan Olberding and Carol Burke were most helpful in securing photographs and illustrations at the Museum of Northern Arizona. lowe a special thanks also to Suzanne Schafer at the University of Arizona Press.
Earlier research appeared, in different form, in two journals: "Soldiers and Scientists in the Petrified Forest," Journal of Arizona History 29 (Winter 1988): 391-412, and in "Protecting Our Forests of Stone," Plateau 61, no. 4 (1990): 24- 31 . I am grateful to the editors of both for permission to repeat here information published in their journals.
To all of the above, thank you.