PAGE 

 nortia, see Vanuxemella. 



Noru'oodia, new genus, described i68 



association i6i 



genotype, Norzvoodia gracilis Walcott i68, 169 



geographic distribution 169 



observations 169 



stratigraphic range 169 



gracilis, new species, described 169 



figured pi. 2y, figs. 2, 2a-g 236 



compared with Norwoodia saffordi , 171 



Norwoodia simplex 171 



Norzvoodia tenera 170 



discussed 168, 169 



formation and locality 170 



observations 170 



ponderosa, new species, described 171 



figured pi. 28, figs, i, la-b 238 



compared with Norwoodia simplex and .V. saffordi 171 



formation and locality 171 



saffordi, new species, described 171 



figured pi. 27, figs, i, la-f 236 



compared with Norwoodia gracilis 171 



Norwoodia ponderosa 171 



Norwoodia simplex 171 



formation and locality 171 



simplex, new species, described 171 



figured pi. 27, figs. 3, 3a-b 236 



compared with Norwoodia gracilis and jV. saffordi 171 



Norwoodia ponderosa 171 



Norwoodia tenera 172 



discussed 168, 169 



formation and locality. ... 171 



tenera, new speecies, described 1 72 



figured pi. 28, figs. 2, 2a-g 238 



compared with Norwoodia gracilis 170 



Norwoodia simplex 172 



discussed 168, 169 



formation and locality 172 



Norwoodidas, new family, described 168 



compared with Ptychoparia, Calymenidje, and the Phacopinae. 168 



Notch Peak formation. Upper Cambrian locality 30W 227 



Nunkoweap Valley, Arizona, Middle Cambrian locality 74 184 



Obolus matinalis Hall, associated with Lonchocephalus chippewaensis. . . . 256 



Obolus parvus Walcott, associated with Vanuxemella nortia 223 



Obolus (JVestonia) ella (Hall and Whitfield), associated with Vanuxem- 

 ella contracta 222 



Olenellus and other genera of the Mesonacidse, publication 160 



Olenellus rcticulatus Peach, compared with Wanneria walcottana 



(Wanner) 220 



