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Olenellus {Holmia) walcottanus Wanner, synonymic reference 219 



Olenoides curticei Walcott, associated with Crepicephalus coosensis 206 



Olenopsis, Sardinian Cambrian genus in America, publication 160 



americanus Walcott, associated with Vanuxemdla contracta 222 



Opisthoparia Beecher, order named I73 



optata, see Millardia. 



Orr formation, Upper Cambrian localities 15J, I5t 185 



Upper Cambrian localities 3oh, 301, 30J 207 



Oryctocephalidse Beecher, family named 220 



Owen, Dr., description of Crepicephalus by 202 



Pagodia thea Walcott, associated with Lonchocephalus chippewaensis, 250, 256 



Paradoxides, compared with Crepicephalus texanus 212 



oelandicus zone, Sweden, Lonchocephalus from 189 



Parkers Quarry, Georgia, Franklin County, Vermont, Lower Cambrian 



locality 25 182 



Pennsylvania, Lower Cambrian locality I2x 220 



Middle Cambrian locality i07d 1/8 



Millardia in 164 



Upper Cambrian locality 107k 165 



Phacopinse, compared with Norwoodid?e 168 



pholus, see Lonchocephalus. 



Pilot Knob, Adams Countj', Wisconsin, Upper Cambrian locality 99a. .. . 199 



Pioche formation. Lower Cambrian locality 31a 205, 209 



plena, see Lonchocephalus. 

 pomona, see Alokistocare. 

 ponderosa, see Norwoodia. 



Potatotop Hill, Burnet County, Texas, Upper Cambrian locality 67a 213 



Potsdam sandstone formation. Upper Cambrian localities 77, 109, iioa, 



III, 136a 194 



Poughkeepsie, New York, Upper Cambrian unnumbered locality near. .. . 197 



Proparia Beecher, order named 161 



genera of, association 161 



prospectense, see Alokistocare. 

 prospectensis, see Ptychoparia. 

 Prospect Mountain, Eureka County, Nevada, Middle Cambrian locaHty 



52a 187 



Prospect Mountain formation. Middle Cambrian locality 52a 187 



Ptychoparia, associated with Crepicephalus coosensis 206 



associated with Vanuxemella nortia 223 



compared with Arrocephalites ? glomeratus 179 



Acrocephalites f majtis 180 



Crepicephalus 200 



Menomoma 162 



Norwoodidse 168 



Saratogia I95 



diademata (Hall), included by error with Saratogia wisconsrnsis 



(Owen) 251 



compared with Saratogia I95 



