234 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 57 



The strong lateral spine on each side of the pygidium is a con- 

 tinuation of the first segment instead of the second as in C. forflcula 

 Sars. In view of the close similarity of the cranidium in the two 

 species, I do not consider the difference in position of the pygidial 

 spine as more than of specific value. 



Formation and locality. — ^Lower Ordovician : Goodsir formation 

 (lower part), at northwest side oi MoUison Creek, elevation 4800 

 feet, on west slope of Mount MoUison ; Ice River Valley, about 10 

 miles southeast of Leanchoil ; west slope of Moose Creek Valley on 

 the east slope of the north ridge of Mount MoUison, elevation 6550 

 feet; Ice River Valley at head of East Fork, elevation 8000 and 8100 

 feet, on the north side of the amphitheater near the top of the ridge 

 overlooking the Ottertail Valley, about 8 miles southwest of Lean- 

 choil on the Canadian Pacific Railway, British Columbia, Canada. 



Collection, J. A. Allan. 



Mr. L. D. Burling found this species at about the same horizon 

 above a cliff of the Ottertail limestone four miles southwest of the 

 mouth of Otto Creek which flows into the Amiskwi River west- 

 northwest of Field, British Columbia, Canada. 



