Marla D. Adkins, _Assistant Editor_ Orin J. Anderson, _Geologist_ Ruben Archuleta, _Technician I_ Robert A. Bieberman, _Senior Petrol. Geologist_ Steve Blodgett, _Assistant Editor_ Lynn A. Brandvold, _Chemist_ James Brannan, _Drafter_ Corale Brierley, _Chemical Microbiologist_ Ron Broadhead, _Petroleum Geologist_ Brenda R. Broadwell, _Assoc. Lab Geoscientist_ Jane A. Calvert, _Assistant Editor_ Frank Campbell, _Coal Geologist_ Richard Chamberlin, _Economic Geologist_ Charles E. Chapin, _Senior Geologist_ Jeanette Chavez, _Admin. Secretary I_ Richard R. Chavez, _Assistant Head, Petroleum_ Ruben A. Crespin, _Laboratory Technician II_ Lois M. Devlin, _Director, Bus.-Pub. Office_ Amelia Dondero, _Metallurgist_ Kathy C. Eden, _Editorial Technician_ Robert W. Eveleth, _Mining Engineer_ K. Babette Faris, _X-ray Lab. Manager_ Rousseau H. Flower, _Sr. Emeritus Paleontologist_ John W. Hawley, _Senior Env. Geologist_ Cindy Howell, _Staff Secretary_ Robert W. Kelley, _Editor & Geologist_ Arleen Lindsey, _Staff Secretary_ Mark Logsdon, _Industrial Minerals Geologist_ David W. Love, _Environmental Geologist_ Wess Mauldin, _Driller_ Virginia McLemore, _Geologist_ Lynne McNeil, _Staff Secretary_ Norma J. Meeks, _Department Secretary_ David Menzie, _Geologist_ Teresa Mueller, _Drafter_ Robert M. North, _Mineralogist_ Keith O’Brien, _Hydrologist_ JoAnne C. Osburn, _Coal Geologist_ Glenn R. Osburn, _Volcanologist_ Barbara R. Popp, _Lab. Biotechnologist_ Marshall A. Reiter, _Senior Geophysicist_ Jacques R. Renault, _Senior Geologist_ James M. Robertson, _Mining Geologist_ Gretchen H. Roybal, _Coal Geologist_ Amy Shacklett, _Asst. Lab Biotechnologist_ Jackie H. Smith, _Laboratory Technician IV_ William J. Stone, _Hydrogeologist_ Samuel Thompson III, _Senior Petrol. Geologist_ Judy M. Vaiza, _Executive Secretary_ Debra Vetterman, _Drafter_ Robert H. Weber, _Senior Geologist_ Betsy Wilson, _Receptionist/Clerk Typist_ Donald Wolberg, _Vertebrate Paleontologist_ Michael W. Wooldridge, _Scientific Illustrator_ Part Time Christina L. Balk, _Geologist_ Howard B. Nickelson, _Coal Geologist_ Beverly Ohline, _Acting Director, Info. Services_ Thomas E. Zimmerman, _Chief Security Officer_ Graduate Students Danny Bobrow James T. Boyle Gerry W. Clarkson Mike Davidson David R. Guilinger Terry Jensen Douglas L. Heath Adrian Hunt Ingrid Klich Ione Lindley Curtis Verpleough John M. Wakefield Mary Lynne Yates John Young Plus about 50 undergraduate assistants _Third edition, 4th printing_ Published by Authority of State of New Mexico, NMSA 1953 Sec. 63-1-4 Printed by University of New Mexico Printing Plant, Albuquerque, April 1982 Available from New Mexico Bureau of Mines & Mineral Resources, Socorro, NM 87801 $4.00