Selectively silicified fauna in base of slope deposits of the Capitan
Formation. The source of silica
was mainly from dissolution of siliceous sponge spicules; replaced grains are mainly calcitic
skeletal fragments including the prominent brachiopod, Leptodus americanus, at the left.
Sample from Geology trail on north wall of McKittrick Canyon, Guadalupe Mountains
National Park, Culberson Co., TX. Coin is 2.4 cm in diameter.
© Peter A. Scholle, 1999