578 C. SCHUCHERT PALEOGEOGRAPHY OF NORTH AMERICA 



Idaho, but during the Middle Triassic the marine area of California and' 

 Nevada was extended into Oregon. The inundation thus started became 

 general in the Upper Triassic all along the Pacific into Arctic Alaska, 

 while in Mexico, for the first time since the Proterozoic,the Gulf of Mexico* 

 spread locally to Zacatecas. The Middle Triassic faunas of the west 

 coast take on more of the Mediterranean type, and are directly correlated 

 with the Ceratites irinodosus zone of Muschelkalk time. The Tethys con- 

 nection is now so marked that, according to Smith, 223 "a paleontologist 

 from Austria might be set down in the Humboldt desert, and he could 

 hardly tell from the character of the fauna whether he was collecting in 

 Bosnia or Nevada." 



The widely distributed Upper Triassic begins in California with Halo- 

 bia beds, followed by an abundant fauna referred to as the Tropites sub- 

 bulatus zone of decided Mediterranean aspect, since many identical spe- 

 cies occur in the two regions, which are more than 6,000 miles apart. 

 With the same fauna appear various species of ichthyosauroids. The last 

 of the Upper Triassic or Norian time returns to northern Asiatic or boreal 

 conditions and widespread faunas, from Siberia to Japan and from Alaska 

 to Peru. The Upper Triassic from Alaska to Vancouver has a limited 

 fauna marked by Pseudomonotis subcircularis. 



Newark series of continental deposits. — In the Connecticut valley there- 

 are from 10,000 to 13,000 feet of red granitic sandstones and shales, with 

 horizons of black f ossilif erous shales and traps. The upper series of sand- 

 stones, conglomerates, and shales, about 3,500 feet in thickness, have 

 diverse types of dinosaur tracks, but very rarely is a skeleton found. The 

 carnivorous forms are represented by Ancliisaurus colurus, A. ( ?) solus, 

 and Thecodontosaurus polyzelus, while the Predentata are present in Am- 

 mosaurus major. Skeletons of a crocodile-belodont reptile, Stegomus 

 longipes, are also found. The middle series of sandstones, shales, and 

 black shales, with three extrusive trap sheets, have a thickness ranging 

 from 2,200 to 3,100 feet, of which the traps show a united depth of be- 

 tween 700 and 900 feet. In the black shales between the traps, represent- 

 ing temporary local bodies of fresh water, are found ganoid fishes of the 

 genera Redfieldius, Semionotus, Diplurus, and Ptycholepis. Of plants, 

 but 11 species are known (far more occur in the Eichmond area) of Oto- 

 zamites latior, Pagiopliyllum simile, P. brevifolium, Clathopteris platy- 

 pliylla, Loperia earolinensis, Cycadinocarpus cliapini, Equisetum, Baeria 

 munsteriana, and Ctenopliyllum brauniunum angustum. There are also 

 tracks of large dinosaurs. 



The lower series of coarse granitic sandstones, with frequent conglomer- 



223 Smith : Festschrift v. Koenen, 1907, p. 408. 



