NO. 3 CAMBRIAN AND OZARKIAN TRILOBITES I3S 



PAGE 



Cedaria proMca Walcott 79 



Fig. 18. (Natural size.) Dorsal view of a nearly entire individual. 

 U. S. Nat. Mus., Cat. No. 70266. 



19. (Natural size.) Cranidium in limestone. U. S. Nat. Mus., Cat. 



No. 70267. 



20. (Natural size.) Pygidium. U. S. Nat. A'lus., Cat. No. 70268. 



21. (Natural size.) Drawing of a free cheek. U. S. Nat. Mus., 



Cat. No. 70269. 



Matrix, limestone nodules in shale or fossils, thickened by growth 

 of fibrous calcite. 



Upper Cambrian, Conasauga formation. (Loc. 91) : Cedar Bluff, 

 Alabama. 



Cedaria tennesseensis Walcott 79 



Fig. 22. (X2.) An entire cranidium. U. S. Nat. Mus., Cat. No. 70270.' 

 23- (X8.) Drawing of protaspis stage. U. S. Nat. Mus., Cat. 

 No. 70271. 



24. (Natural size.) Associated free cheek. U. S. Nat. Mus., Cat. 



No. 70272. 



25. (Natural size.) Associated pygidium. U. S. Nat. Mus., Cat. 



No. 70273. 



Matrix, soft purple shale. 



Upper Cambrian, Nolichucky shale. (Loc. 107a) : Northwest of 

 Knoxville, Tennessee. 



Chancia ebdome Walcott 80 



Fig. 26. (Natural size.) Dorsal shield with 20 thoracic segments. U.S. 

 Nat. Mus., Cat. No. 70274. 



Matrix, shale. Specimens not entirely flat. 



Middle Cambrian, Spence shale. (Loc. 55c) : Bear Lake County, 

 Idaho. 



Chancia eva.v Walcott 81 



Fig. 27. (Natural size.) A large dorsal shield with about 24 thoracic 

 segments. Pygidium and free cheeks broken away. U. S. 

 Nat. Mus., Cat. No. 70275. 



Matrix, shale. 



Middle Cambrian, Spence shale. (Loc. S5c) : Bear Lake County, 

 Idaho. 



Armonia pelops Walcott 69 



Fig. 28. (Natural size.) Slightly crushed entire dorsal shield. U. S. 

 Nat. Mu?., Cat. No. 70276. 



29. (Natural size.) Cranidium preserving convexity and form. 



U. S. Nat. Mus., Cat. No. 70277. 



30. (Natural size.) A large slightly crushed cranidium. U. S. Nat. 



Mus., Cat. No. 70278. 



31. (Natural size.) Posterior part of thorax with pygidium at- 



tached. U. S. Nat. Mus., Cat. No. 70279. 



Matrix, shale. Specimens not completely flat. 

 Upper Cambrian, Conasauga formation.. (Loc. 95) : Cowan 

 Creek, Alabama. 



