NO. 5 UPPER CAMBRIAN TRILOBITES RESSER III 



PLATE 2 



PAGE 



Chariocephalus zvichitacnsis, new species lo 



1-3. Dorsal, side, and front views of holotype cranidium (X i-S)- 



4. A larger, less perfect cranidium. 



5, 6. Libragenes. 



7, 8. Associated pygidium (X i-5)- 



Honey Creek limestone; (loc. giq) 8 miles southeast of Mountain View, 

 Wichita Mountains, Oklahoma. 



Chariocephalus ulrichi, new species 1 1 



9, 10. Side and dorsal views of holotype cranidium (X 3)- 



11. Libragene. 



12. Front and oblique views of cranidia (X i-S)- 



13. 14. Side and dorsal views of the pygidium (X i-S)- 



Honey Creek limestone; (loc. gy) 2 miles southeast of Canyon Creek, 

 Wichita Mountains, Oklahoma. 



Chariocephalus magnus, new species 11 



15-17. Holotype cranidium. (See also pi. 12, fig. 13.) 

 Lyell formation; (loc. 2oj) Tilted Mountain Brook, 9+ miles east of 

 Lake Louise, Alberta. 



Chariocephalus hadgcrensis, new species 12 



18-20. Exfoliated holotype cranidium (X2.5). 



Lyell formation; (loc. iQu) Badger Pass, Johnson Canyon, 8 miles east 

 of Lake Louise, Alberta. 



Chariocephalus burlingi. new species 12 



21. Holotype cranidium (X 1.5). 



Lynx formation; (loc. 190) lyatunga Mountain, Robson Peak District, 

 British Columbia. 



Irvingella silvestris, new species 13 



22-24. Side, front, and dorsal views of holotype cranidium (X2). 

 25-27. A larger, partially exfoliated cranidium (X i-5)- 

 Honey Creek limestone; (loc. 89w) west side of the West Timbered 

 Hills, Arbuckle Mountains, Oklahoma. 



Irvingella arbucklensis, new species 14 



28-30. Front, dorsal, and side views of the holotype cranidium (X i-S)- 

 31, 32. Similar views of another cranidium (X2). 

 33. An incomplete cranidium (X i-S)- 



Honey Creek limestone; (loc. Sgw) west side of the West Timbered 

 Hills, Arbuckle Mountains, Oklahoma. 



Irvingella mesleri, new species • 15 



34-36. Dorsal, side, and front views of the holotype cranidium (X3)- 

 37, 38. An incomplete cranidium (X3). 



Honey Creek limestone; (loc. i2n) 7 miles north of Springer, Arbuckle 

 Mountains, Oklahoma. 



Irvingella recurva, new species 15 



39-41. Dorsal, front, and side views of the holotype cranidium (X2). 

 Honey Creek limestone; (loc. 12m) 7 miles north of Springer, Arbuckle 

 Mountains, Oklahoma. 



Irvingella alia, new species 16 



42-44. Dorsal, front, and side views of the holotype cranidium (X2). 

 45-47. A larger cranidium (X i-5)- 



Honey Creek limestone; (loc. gp) about 15 miles northwest of Fort 

 Sill, Wichita Mountains, Oklahoma. 



Irvingella davisensis, new species 16 



48. Holotype cranidium (X4)- 



Davis formation; (loc. 22m) Shaw Branch, Davis Creek, Missouri. 



Irvingella ottertailensis, new species 17 



49. Impression of holotype cranidium (X2.5). 



"Goodsir" formation; Moose Creek, Ottertail Range, British Columbia. 



