Texas, Princeton, The John Crear Library, The United States 
Geological Survey, Stuart Levinson, Morton Stephenson, 
Harbans Puri, and Tetsuro Hanai. 
I gratefully acknowledge much help from the following, 
who have over the years exchanged publications with me, sent 
me holotypes or topotypes of their species, or have made 
special collections from topotype localities for me, or who 
have located publications for me that I needed in this work: 
Charles Ivan Alexander, Dallas, Texas; R. S. Bassler, U. S. 
National Museum, Washington, D.eC.; the late Daniel Blake, 
Baton Rouge, Louisiana; the late Dr. J. He Bonnema, Groningen, 
Netherlands; Bedrich Boucek, Prague, Czechoslovakia; the 
late Frederick Chapman of Australia; Robey H. Clark, New 
Orleans, Louisiana; Alan Cheetham, Baton Rouge, Louisiana; 
He. Ne Coryell, Columbia University, New York; Robert Crouch, 
Houston, Texasj Carey Croneis, Houston, Texas; Christian F. 
Dohm, New York City; Richard Edwards, Gainesville, Florida; 
A. De Ellis, Jr., Houston, Texas; Harold N. Fisk, Houston, 
Texas; Julius Garrett, Houston, Texas; N. Grekoff, Rueil-- 
Malmaison, Seine-et-Oise, France; Wade Hadley, Jr., Caracas, 
Venezuela; Tetsuro Hanai, Tokyo, Japan; Reginald W. Harris, 
Norman, Oklahoma; Gunnar Henningsmoen, Oslo, Norway; Ivar 
Hessland, Uppsala, Sweden; Bernard Hill, New Orleans, 
Louisiana; Keith Hussey, Ames, Iowa; Merle C. Israelsky, 
Pasadena, Californias Ne de Be Hornibrook, Wellington, New 
xi 
