I02 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 75 



KAINELLA BILLINGSI (Walcott) 



Plate 22, figs. 1-7 



Hungaia billingsi Walcott, 1913, Smithsonian Misc. Coll., Vol. 57, No. 12, 

 p. 336 (listed only) ; idem, 1924, Vol. 75, No. i, p. 27, fig- 7- 



Observations. — This species, known only from the dissociated 

 parts, is the largest of six species determined from the locality. The 

 presence of so large a number of species makes it impossible to be 

 altogether certain that the pleurae, pygidium, and free cheeks here 

 assigned to this cranidium actually belong together. Most species of 

 this genus have been founded on the pygidium, one of which 

 (H. flagricaudus) was long ago described by White, as these parts 

 are more readily distinguishable one from the other than the cranidia. 

 AH that can be said with respect to the grouping of the parts here 

 assigned to K. billingsi is that if seems most natural after a study of 

 the available material. 



The illustrations, together with the generic diagnosis, give the 

 characters of the species. 



Specific name is given in honor of Elkana Billings, a pioneer 

 paleontologist of the Geological Survey of Canada. 



This is a widely distributed genus in the Cordilleran area of 

 western Canada and the United States. Thus far it has been found 

 only in dismembered fragments of the dorsal shield, but usually in 

 great quantities of one or two species. Altogether 20 species have 

 thus far been differentiated. 



The Kainella zone is a well-marked horizon in the lower part of 

 the upper third of the Mons formation and thus far it has been 

 found to be a serviceable unit in comparing stratigraphic sections. It 

 has a known vertical range from a few feet up to 130 feet (39.6 m.). 



The described species referred to the genus are : 



Dicellocephalus ? Aagricaudus White, 1874. See U. S. Geol. Surv. Bull. 

 30, 1886, p. 185, pi. 25, fig. 4. 



Dicellocephalus inexpectans (Walcott), 1884. Monogr. U. S. Geol. 

 Surv., Vol. 9, p. 90, pi. I, fig. 10. 



Formation and locality. — Ozarkian : (6iq) Chushina formation. 

 Gray limestone in beds of varying thickness, one or two layers quite 

 ferruginous. In Billings Butte (Extinguisher) at end of west spur 

 of Mount Lynx, above Hunga Glacier and east of Robson Peak, 

 Robson Park, northwest of Yellowhead Pass, in eastern British 

 Columbia, Canada. 



