Figure 7.--Triangular diagrams showing petrographic classification of sandstones from the Minturn and Sangre de Cristo Formations: A) Q-F-L, quartz-feldspar-lithic fragments (terminology of McBride, 1963), B) G-C-M, detrital grains-calcite cement-matrix (<0.03 mm), and C) Q-K-P, quartz-potassium feldspar-plagioclase.