field trip leaders: Donald F. Reaser, Priscilla P. Nelson, Joe C. Yelderman ; 1990 GSA annual meeting field trip chairmen: Robert T. Clarke and Kent C. Nielsen
field trip leaders, William C. Dawson, Charles L. McNulty, Donald F. Reaser ; compiled by Donald F. Reaser ; field trip co-chairmen and editors, David E. Eby, Robert T. Clarke