INDEX 437 



Alberta — Continued. page 



photograph showing Bow Vallej- pi. 45, fig- i 



relative position and thickness of Cambrian formations in 2 



topography of Bow Valley. 424 



unconformity between Cambrian and pre-Cambrian in 426-427 



alberta, see Nisusia. 



Albertella, a descendant of the Mesonacidse 254 



new genus, described and discussed 18 



compared with Olenellus and Mesonacis 19 



Parabolina and Hysterolinus ig 



Zacanthoides 18, 19 



bosivorthi, new species 22, pi. i, figs. 4-7 



compared with Albertella Helena 22 



mentioned 22 



stratigraphic position and association 214 



Helena, new species 19, pi. 2, figs. 1-9 



associated species on Gordon Creek, Montana 21 



compared with Albertella boszvortHi 22 



ZacantHoides idahoensis 29 



mentioned 22, 61 



stratigraphic position and association 202, 214 



sp. undt., stratigraphic position and association 213, 214 



Albertella fauna, in Montana and British Columbia, stratigraphic position 



discussed 203 



Algonkian sediments, fresh-water origin of 252 



alta, see Acrotreta idaHocnsis. 

 americanus, see Hyolithes. 

 amii, see Nisusia (Jamesclla). 



Amphion, compared with Schmalenseeia 14 



aniphiontira, see ScHmalenseeia. 

 ampla, see Lingulella. 



Andrarum, fossils from 290 



Annelidian-like ancestor, development of Mesonacidce from 249 



annulatiis, see Hyolitliellus. 

 anomala, see Wimanella. 



Anomalocaris f ? acutangula, stratigraphic position and association 211 



canadensis, stratigraphic position and association 211 



f whiteavesi, stratigraphic position and association 211 



Anomocare, stratigraphic position and association 176, 178, 179, 192, 193 



Anse au Loup, see L'Anse au Loup. 



Anterior border segment defined 238 



Anterior glabellar lobe in the Mesonacidae discussed 242 



Anterior lateral (Retractor) muscles, defined 154 



Anterior region, defined 154 



Apex, defined 154 



Apical callosity, defined 154 



apollinis, see Obolus. 



appalachia, see BiUingsella. 



Apiis, eye of compared with that of Limuliis 239 



