Geological Society of Iowa:

The Geological Society of Iowa (GSI) is a non-profit corporation whose objective is to advance the science of geology, especially Iowa geology. GSI publishes a newsletter twice a year which informs members about newsworthy geological happenings in Iowa and elsewhere, GSI business, and details of upcoming field trips and meetings. Generally, GSI conducts two field trips a year, one each in the spring and fall. The spring field trip coincides with the spring meeting of the Iowa Academy of Science. The fall GSI field trip usually concludes with a banquet and short business meeting. Guidebooks for each field trip are free to members attending the trip and, upon request, free to all members within one year of the trip.