LIFE 



419 



Fig. 367. REPRESENTATIVE HAMILTON FOSSILS: a, Fencslrlla cnniciuta Hall, 

 t\l>r of bryozoan common in the Middle Devonian; b, Arthracaiilha punctobrachi- 

 iitii Williams, one of a genus of crinoids restricted to the Middle and Upper Devo- 

 nian; c, Elcuthcrocrinus cassedayi S. and Y., a peculiar, irregular blastoid; during life 

 it probably rested upon one side on the sea bottom, d, Echiiwcaris punctata (Hall), 

 a crustacean more highly organized than the trilobites. e-j, brachiopods: 

 e, Tropidolcptuscarinatus (Con.) ;/ and /, Chonctcs coronal us ( Con.) ; g, Vihiliiui pnstii- 

 losa Hall; //, Rkipidometta imnuxi'mi Hall, a representative of the orthids, whu h 

 had neat development in the Devonian; j, Spirifcr pi'iiinilns (At\v.), one of the 

 long-hinge-lined spirifers most conspicuous in the Middle and Upper Devonian; 

 , /, and HI. pefecypods: k, Cypricarddla bcllislr'niliis (Con.); /, J'i<rinc>i jlabella 

 (Con.); m, PtuaottetU cmistrida (Con.); three pelecypods common in the Hamilton. 

 n, Loxoncma hamillnnhf Hall, a gastropod common in this epoch; o, Goniatitcs 

 vtiiiiixftni (Hall), a characteristic cephalopod of this fauna; p, Phacops rana (Greene) 

 the most common trilobite of the Hamilton, and representative of a genus \vhii h 

 has its greatest expansion in the Devonian; q, Cryphoeus bootlii (Ireene, one of the 

 last of the dalmanites. 



hung with wonderful persistence, not unlike the debased human 

 class which it has come to typify. 



Northwestern Hamilton fauna. While the preceding fauna was 

 developing in the eastern interior sea, another fauna was evolving 

 on somewhat different lines in the northwestern sea which over- 

 sprrad a large part of the northwestern interior (fig. 358). For a 

 time this northwest sea was not in communication with the sea in 



