TYPICAL SUNDANCE AND MORRISON SECTIONS 253 



Feet 



Coarse, heavy-bedded, buff sandstone. About 10 



Green to buff sandy shale with Ostrea strigilecula, Pseudomo- 

 notis (Eumicrotis) curta, Belemnites densus, and Cardioceras 



cordiforme. Weathers rapidly. About 20 



Red and white sandstone and red shale, passing upward into thin- 

 bedded, white, coarse sandstone somewhat conglomeratic at the 

 top. About., 22 



Total 157 



Break in deposition. 

 Triassic. Chugwater red sandy shales between white sandstones. 



FREEZEOUT HILLS, WYOMING 



North of Medicine Bow. Adapted from W. C. Knight, Bulletin of the 

 Geological Society of America, volume 11, 1900, pages 381-382. 



Feet 

 Comanchian. Cloverly conglomerate and sandstone. Originally called 

 Dakota sandstone. 

 Probable break in deposition. 

 Morrison formation. Drab marls and clays, with some thin sandstones 



having dinosaurs 55 



Hard clay and sandstone with naiids and teeth of crocodiles ... 1.5 

 Drab marls and clays with a few beds of calcareous sandstones. 

 Has Allosaurus f^'agilis, Dlplodocus longus, Brontosaurus ex- 

 celsus, Morosaurus grandis, Stegosaurus ungulatus, Campto- 



saurus dispar, Ceratodus, and turtles 24.5 



Drab marls and clays with thin soft sandstones 46 



Yellowish soft sandstone with cycads and wood 10 



Brown sandstone, cross-bedded 2 



Drab shales, clays, and marls 70 



Greenish sandstone 4 



Total 213 



Break in deposition. Knight notes this "unconformability" as "ap- 

 parent" and adds that it has "not yet been detected." 

 Jurassic. Sundance (Knight's Shirley) formation. 



Reddish and brown shales and clays 49 



Dark limestone with Camptonectes and Ostrea 2 



Greenish shales with dark bands of clay and sandstone, and 

 many concretions replete with nests of invertebrates and an 



occasional Baptanodon and Plesiosaurus 50 



Gray sandstone 4 



Brownish shales with concretions having a few fossils 44 



White sandstone witli fossils at the top 30 



Total 179 



Break in deposition. 

 Triassic. Red sandstones, etcetera. 



