ILLUSTRATIONS 



PLATES TO FACE PAGE 



1. Cambrian Trilobites {Bathyuriscus, Alhertella, Bnrlingia, 



Oryctocara) 42 



2. Cambrian Trilobites {Alhertella) 44 



3. " " (Zaeanthoides) 46 



4. " " (Neolemis) 48 



5. " , " (Neolemis) 50 



6. " " (Neolenus) 52 



7. Cambrian Brachiopoda ( Atremata) 1 18 



8. " " (Atremata and Neotremata) 120 



9. " " (Neotremata and Protremata) . . . . 122 



10. " " (Protremata) 124 



11. Schematic Diagram of evolution of Cambrian Brachiopoda. 140 



12. Microphotographs of brachiopod shell sections 164 



13. Map of House Range, Millard County, Utah 172 



14. West face of Notch Peak, House Range, Utah 173 



15. Fig. I. Eastern side of the House Range south of Marjum 



Pass, Utah 178 



Fig. 2. Ridge east and southeast of Antelope Springs, 



House Range, Utah 178 



16. North side of Dome Canyon, House Range, Utah 182 



17. West face of House Range beneath Tatow Knob, Utah. . . . 184 



18. Lower Cambrian quartzites, Inyo County, California 186 



19. Eastern side of Sherbrooke Ridge, British Columbia 207 



20. Fig. I. North Ridge of Castle Mountain, Alberta 209 



Fig. 2. Southeast front of Castle Mountain, Alberta 209 



21. Mount Stephen, British Columbia, from .the north 210 



22. Ridges southeast and west of Lake Louise, Alberta 216 



23. Cambrian Trilobites (Nevadia) . . . 380 



24. " " {Elliptocephala, Olenellusf, Pcpdeu- 

 mias) 382 



25. Cambrian Trilobites {Elliptocephala, Peedeiimias) 384 



26. " " {Mesonacis) 386 



27. " " . {Callavia, Holmia) 388 



28. " " (Callavia) 390 



(vii) 



