Rock Type Landforms Thickness Paleoenviron. Remarks Age Shale interlayered Floodplains and 65 Mesaverde Formation Caps Mancos Shale MYA 300 - 400 ft with sandstone Costal Areas Mostly dark gray Factory Butte Mancos Shale 2000 - 3000 ft shale interlayered An interior seaway and badlands with sandstone near Caineville Tan sandstone with Locally absent; Cretaceous 0 -50 ft oyster shell fossils Coastal Oyster Shell Reef Dakota Sandstone Conglomerate and Found in Northern Part Cedar Mountain Formation 0-100 ft Rivers and Floodplains of Cathedral Valley Mudstone Layers 144 White crossbedded sandstone MYA Brushy Basin Member Vast river systems; Bentonite Hills Morrison 180 - 700 ft (Salt Wash) & candy-striped bentonite clays from are in Brushy Basin Formation mudstone (Brushy Basin) altered volcanic ash Member Salt Wash Member Thinly-bedded, Inconspicuous 150 - 300 ft reddish-brown Tidal flats in Capitol Reef Summerville Formation siltstone area Grayish-green Caps cathedrals of 0 - 80 ft sandstone & gypsum Marine Cathedral Valley Curtis Formation Earthy, red, very 450 - 750 ft fine-grained Tidal flats Cathedrals of sandstone & gypsum Cathedral Valley Entrada Sandstone Interlayered red Transitional between Forms red V-shaped 300 - 1000 ft sandstone & gypsum marine and continental folds on east side of Carmel Formation Waterpocket Fold San Rafael Group Jurassic Red, ledge forming Sand dunes Page Sandstone 50 - 100 ft sandstone Cap of Golden Throne White crossbedded Sahara desert-like Capitol Dome, 800 - 1100 ft sandstone sand dunes Navajo Dome, & Navajo Sandstone Grand Wash Narrows Interlayered red Southwest Top, ledgy portion 350 ft sandstone & siltstone flowing rivers of Fruita Cliffs Kayenta Formation Massive sandstone; 350 ft Sand dunes Fruita Cliffs Wingate Sandstone weathers dark red & Circle Cliffs 206 Glen Canyon Group MYA Interlayered sandstone Forested basin with Slopes below Fruita 350 - 550 ft siltstone, & bentonitic rivers, swamps, & Cliffs; contains mudstone lakes petrified wood & Uranium Chinle Formation White sandstone River channels Discontinuous; cap 0 - 90 ft of Chimney Rock Shinarump Member Mostly dark red Triassic siltstone & Westward sloping Miners Mountain, 500 - 1000 ft mudstone; minor coastal plain, fluctuating Egyptian Temple, & Moenkopi Formation yellowish limestone sea level base of Chimney Rock 248 Gray dolomitic MYA 70 - 100 ft limestone Marine Fremont River Gorge Kaibab Limestone White crossbedded Beach & Fremont River Gorge 400 + ft sandstone dune sands & Goosenecks of White Rim Sandstone Sulphur Creek 290 MYA Permian MYA = Million Years Ago Text & Design by Allyson Mathis Graphics & Artwork by Matt How Updated 6/20/2009 by Adam Hiscock.