In general, integration of spatial information can be difficult for students. To study students' spatial thinking and their self-efficacy of interpreting stratigraphic columns, we designed an exercise that asks college-level students to interpret problems on the principles of superposition, original horizontality and lateral continuity, and geologic time using text and symbols. The exercise was designed with two goals in mind: to determine the level of student confidence and cognition and to test the effectiveness of this type of exercise in large-enrollment courses. Overall, students performed well on symbolic representations of the columns, but reported low self-efficacy of their interpretations. The opposite occurred with the short-answer questions. Results suggest that these students are more comfortable with verbal questions, but they lack the ability to synthesize complete answers to diverse questions. Students also tended to feel less comfortable with questions where they had to convert text to a symbolic representation. We found this type of assignment to be extremely useful with a large class, as it elicited much information about student learning without taking extensive time to evaluate. Implications for geoscience educators include the need to incorporate techniques to improve the completeness of student responses on problems that require synthesis.