The development of a computer self-test program in geology at Macalester College, Minnesota, is described. Based on the philosophy that tests, particularly those involving no grading, are useful study devices, computers are used to make tests available to students. Ten lessons have been developed on different topics in geology, and the computer program for handling multiple choice tests is written in BASIC. Additionally, the number of times a question is tried and the number of times the correct answer is selected as a first choice is recorded in order to help determine how much class time to devote to various course topics. Microcomputers were implemented to enable the use of graphs, cross sections, or maps. Among other questions, the lesson asks students to arrange the rock units and the periods of erosion, folding, and faulting in order of relative age. Student reactions to the use of the computer were assessed based on questionnaire responses. The computer tests and lessons are used as an addition to the conventional lecture, discussion, and laboratory approach. The chief benefits of the computer lessons are: they provide a good means for review of subject matter, they help to identify problem areas, the computer recordkeeping provides the instructor with information on how well the class is learning various concepts and principles, and most of the students taking the computer tests or lessons have had no previous computer exposure. (SW)