758 



HISTORICAL GEOLOGY. 



Badiotites Carlottensis, Aulacoceras Carlottensis ; from northern Vancouver, Arcestes 

 Gabbi Sind Arniotites (Balatonites) VcDu-oitverensis ; from Liard Kiver, about r)0° 16' N. 

 and 125° 35' W., Spirifer borealis, Terebratula Liardensis, Halobia {Ddonella) Lommeli, 

 H. occidentalis, Monotis subcircularisG&bh (probably = PsPAidomonotis Ochotica of Keysev- 

 ling), Nautilus Liardensia (near N. Sibyllce of Spitzbergen) , and Trachyceras Canadense 

 (1889). All are of the Upper Trias. 



Of Fishes, few species are known. 



Several Saurian vertebrae are mentioned by King as having been observed in the 

 Trias of western Nevada, and Hyatt speaks of fragments of Vertebrates in the Sierra 

 Nevada Triassic. A large Crocodilian of the genus Belodon has been described by Cope, 

 from the Gallinas valley in the Sierra Madre Mountains, New Mexico, under the name 

 Typolhorax coccinarum. Bystrophceus vicemalm Cope (1877), found by Newberry in 

 Painted Caiion, southeastern Utah, is supposed to be a Dinosaur. 



Although Amphibians are many and of great size in Europe at this era, no remains 

 are yet known from the western half of North America. 



Jurassic Formation. 



The Jurassic beds are mucli less barren in fossils than the Triassic, and 

 yet are seldom prolific in species. Gastropods are rare, and Cephalopods 

 not numerous. Invertebrate species were first discovered in them by Meek, 

 at the Black Hills, where the species here figured occur along with many 

 others. The Crinoid disk, Fig. 1192, is of the genus Pentacrinus. A species 



1193. 



1192-1197. 



1194. 



1196 a. 



1196. 



Fig. 1192, a segment of the column of Pentacrinus asteriscus ; 1193, Monotis curta ; 1194, Trigonia Conradi ; 

 1195, Tancredia Warreniana ; 1196, Quenstedioceras cordiforme ; 1196 a, side view of same, a little reduced ; 

 1197, Belemnites densus. Meek. 



of the Ammonite group is represented in Figs. 1196, 1196 a. The Belemnite, 

 Belemnites densus Meek, Fig. 1197, is from these beds, which have been 

 named by Marsh the Baptanodon beds. (These Baptanodon beds, near 

 Como, Colorado, are marine, and overlie Ked beds which are referred to the 

 Triassic; above them are the freshwater Atlantosaurus beds of Marsh, and 

 overlying these comes the Dakota group.) The fossil here represented is 

 the lower end of the internal bone answering to the bone of the Squid, but 

 differing from those of modern species in the texture and weight of the 



