Angular unconformity with Quaternary travertine overlying tilted Mesozoic sandstones and shales, Cody, WY |
Disconformity between massive Coconino Sandstone and thinner bedded Hermit Shale, Grand Canyon National Park, AZ |
Grand Canyon Series overlies the Vishnu Group in a non-conformity relationship, Grand Canyon National Park, AZ |
(STRA4) Nonconformity between Cambrian Potsdam Fm. and Proterozoic Gneiss, Alexandria Bay, NY |
Petrified Wood Petrified Forest National Park, AZ |
Petrified wood weathers out of the Triassic Chinle Fm., Petrified Forest National Park, AZ |
(STRA7) Mudcracks in the Proterozoic Snowslip Fm., Logan Pass, Glacier National Park, MT |
(STRA8) Archean pillow lavas tilted on end with the top to the left, Shebondawan, Ontario, Canada |
(STRA9) Non-conformity between Pennsylvanian Fountain Fm. and underlying Proterozoic metamorphic rocks, Red Rocks Park, CO |
(STRA10) Top view mudcracks. |
(STRA11) Cross section of same mudcracks |
(STRA12) Load casts, flute marks, and drag grooves, Normanskill Shale, Greene County, NY |
(STRA13) Raindrop imprints and mudcracks in the Proterozoic Appekunney Fm., Glacier National Park, MT |
(STRA14) Recent mudcracks and mud curls, IL |
(STRA15) Mudchips in Proterozoic Grinnell Fm., Glacier National Park, MT |
(STRA16) Mudcracks in the Proterozoic Grinnell Fm., Glacier National Park, MT |
(STRA17) Asymmetrical ripple marks in the Proterozoic Snowslip Fm., Glacier National Park, MT |
(STRA18) Symmetrical ripple marks in the Proterozoic Lorrain Fm., Desbarats, Ontario, Canada |
(STRA19) Asymmetrical ripple marks in sand caused by the current of the Colorado River, Lees Ferry, AZ |
(STRA20) Asymmetrical ripple marks with current from left to right. |
(STRA22) Asymmetrical ripple marks (current from top to bottom) on sandstone tilted on end, Ontario, Canada |
Stylolites in oolitic limestone, IA |
(STRA24) Channel cut and fill in Triassic Moenkopi Fm, near Holbrook, AZ |
(STRA25) Graded bedding (turbidites) allows determination of top of folded beds, Proterozoic Vermillion Lake FM., Tower, MN |
(STRA26) Graded bedding (top to upper left) in vertically dipping Proterozoic turbidites of the Lake Vermillion Fm, Tower, MN |
(STRA27) Close-up of graded bedding in the Proterozoic Vermillion Lakes Fm., Tower, MN |
(STRA28) Sandstone pinch out in shales in the Jurassic Morrison Fm. near Green River, WY |
(STRA29) Sandstone with variable concentrations of iron oxides, UT |
Fluting in soft shales of the Ricardo Fm., Red Rock Canyon State Park, CA |
(STRA31) Complex ripples in Proterozoic Snowslip Fm., Glacier National park, MT |
(STRA32) Continental redbeds underlie gray marine layers of the Devonian Catskill Fm. near Scranton, PA |
Rounded and flattened cobbles along the shoreline of Lake McDonald, Glacier National Park, MT |
(STRA34) Turbidites in Mississippian Tesnus Fm. near Marathon, TX |
(STRA35) El Capitan, a Permian reef deposit, Gaudalupe Mountains National Park, TX |
Cross bedding in Jurassic Navajo Sandstone, North Coyote Buttes, AZ |
(STRA37) Mudballs in continental redbeds of the Devonian Catskill Fm., Scranton, PA |
(STRA38) Shale and limestone facies in Pennsylvanian rocks at Cagles Mill Dam site, IN |
Navajo Twins show differences in bedding of Jurassic Bluff Ss. (massive) and Summerville Fm. (thin), Bluff, UT |
(STRA40) Cross cutting relationships in igneous intrusions. |
(STRA41) Fluvial cross-bedding in the Cambrian Chapel Rock Fm., Pictured Rocks National Lakeshore MI |
(STRA42) Proterozoic Gunflint Chert contains cyanobacteria 1.9 BY old, Kakabek Falls, Ontario, Canada |
(STRA43) Debris flow breccia in Mosaic Canyon, Death Valley National Park, CA |
(STRA44) Coal in the Jurassic Fernie Fm., Alberta, Canada |
(STRA45) Asymmetrical ripple marks, Monument Valley, AZ |
(STRTA46) Well rounded, sorted, and frosted quartz grains, Ordovician St. Peter Sandstone, IL |
(STRA47) Quartz pebbles with mostly high roundness and moderate sphericity, Pennsylvanian Potsville Conglomerate, Scranton, PA |
Asymmetrical ripple marks in the Moenkopi Fm., Capitol Reef National Park, UT |
Checkerboard Mesa cross-bedding, Zion National Park, UT |
Geologist at Checkerboard Mesa, Zion National Park, UT |
Coal Mine Canyon cut and fill. AZ |
Chalk deposits at Monument Rocks National Natural Landmark, KS |
White River Formation, Badlands National Park, SD |
Wet beach cobbles, Lake McDonald, Glacier National Park, MT |
Cross-section of debris flows and angular unconformity, Phoenix, AZ |