Correlation of Arizona Paleozoic formations

ACKNOWLEDGMENTS Grateful acknowledgments are due to Professor Charles Schuchert, of Yale University, who, while lecturing at the University of Arizona in 1924–1925, made a donation that enabled the writer and his students to start their research in stratigraphic paleontology in that State; to Dr. David White and Dr. J. C. Merriam, through whose kind interest the writer was provided with means to extend his work to the Grand Canyon area and later to visit the museums at Washington, New York, and Albany ; to Dr. G. M. Butler, who secured for the writer the opportunity of working through a number of summer seasons in connection with the program of the Arizona Bureau of Mines, and also to the staff of that Bureau; to Miss Clara Mae LeVene for her kind assistance in preparing the manuscript; and to the writer’s former students, H. Bruhn, R. R. Reid, W. L. Thomas, . . .