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Yosemite National Park, California. Bold exposure of unjointed Half Dome Granodiorite (in sun) capped by mostly well-jointed tonalite (in shade) making up Glacier Point. The contact between the two rock types angles upward to the left. Figure 38, U.S. Geological Survey Bulletin 1595.
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Yosemite National Park, California. Cascade Cliffs and Little Yosemite Valley. In few other places in the Yosemite region is the granite more continuously massive than in the Cascade Cliffs. Only one horizontal master joint divides the rock (in the lower left.) The scales on the cliffs are merely surficial features due to exfoliation. The dark streaks indicate the paths followed by the ribbon cascades which descend from the upland in the spring, when the snow is melting, and from which the cliffs take their name. In the background is Sugar Loaf (Bunnell Point). Circa 1914. Plate 45-A, U.S. Geological Survey Professional paper 160. Note: The Francois E. Matthes' papers and field notebooks are housed in the Brancroft...
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Yosemite National Park, California. Imprints on the rock left by passing debris-laden ice. Glacial polish and striations. Polished surface layer flakes off, and this evidence of glaciation gradually disappears. This excellent and accessible exposure is at the foot of Polly Dome along Tioga Road on the north side of Tenaya Lake. Figure 55-B, U.S. Geological Survey Bulletin 1595.
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Yosemite National Park. Snow scene along Sugar Pine-Redwood Creek trail at Forest Service Administrative site. Mariposa quadrangle. California. October 3, 1916. F-stop 22, 1/5 seconds.
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Cascade Cliffs and Little Yosemite valley. In few other places in the Yosemite region is the granite more continuously massive than in the Cascade Cliffs. Only one horizontal master joint divides the rock (in the lower left) The scales on the cliffs are merely surficial features due to exfoliation. The dark streaks indicate the paths followed by the ribbon cascades which descend from the upland in the spring, when the snow is melting, and from which the cliffs take their name. In the background is Sugar Loaf (Bunnell Point). Yosemite National Park. Mariposa County, California. ca. 1914. Published as plate 45-A, in U.S. Geological Survey. Professional paper 160. 1930. Note: The Francois E. Matthes' papers and field...
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Yosemite National Park, California. Dike of light-colored, fine-grained aplite crosscutting granodiorite. Aplite is a silica-rich rock composed chiefly of quartz and potassium feldspar. Figure 13, U.S. Geological Survey Bulletin 1595.
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Yosemite National Park, California. El Capitan Granite. Rock surface chemically etched and stained to differentiate potassium feldspar (orange- yellow), plagioclase (red), and quartz (uncolored). Figure 10-B, U.S. Geological Survey Bulletin 1595.
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Porphyritic texture in Cathedral Peak Granodiorite, with potassium feldspar phenocrysts much larger than the other minerals in the rock matrix. Yosemite National Park. California. n.d. Published as figure 14 in U.S. Geological Survey. Bulletin 1595. 1987.