Do students really enroll in Introductory Geology because they think it is "rocks for jocks"? In this study, we examine the widely held assumption that students view geology as a qualitative and remedial option for fulfilling a general education requirement. We present the first quantitative characterization of a large number of Introductory Geology students, their demographic characteristics and motivations at the start of the course, and their reasons for enrolling. More than 1,000 undergraduate students from seven institutions across the U.S. participated in this study, providing demographic information and responses to the Motivated Strategies for Learning Questionnaire. Students taking Introductory Geology either to fulfill a general education requirement (72% of the survey population) or because they thought it would be easy (19%) had relatively low motivation. The youngest students (18 or 19 years, 62% of the survey population) and those who had not declared a major or were planning a nonscience major (79%) also had relatively low motivation. In contrast, students taking the course for a major or minor (26%), because of prior interest in geology (31%), or because of interest in the interactions between humans and the environment (15%) had relatively high motivation. The differences in motivation we identify have important implications for Introductory Geology instructors, particularly those teaching large-enrollment courses, and validate the need for understanding student characteristics when designing course goals and selecting instructional strategies.