231. Stratigraphy. Principles of organizing strata into units based on their lithologic character, their age relationships, and their fossil content. Interpretation of vertical and horizontal stratigraphic relationships. Surface and subsurface correlation techniques, with emphasis on the use of microfossils in subsurface correlation. Radiometric and magnetic dating of stratigraphic units. Critical evaluation of the regional stratigraphy of a selected area. Field trips. Prerequisite: 220. [3] Siesser. (Offered in alternate years)