164 0. D. Walcott — Cambrian Fossils from Mi. Stephens. 



The next superior fauna to the Olenoides of No. 21, is that 

 occurring in No. 23, of the Highland section. It is of Upper 

 Cambrian or Potsdam age, and contains : Bellerophon antiqua- 

 tus, Pleurotomaria (3 undetermined species), Hyolithes (3 new 

 species), Dicellocephalus Pepinensis, Dicellocephalus (type of 

 D. Minnesotensis), Dicellocephalus sp., Ptychoparia [Euloma f) 

 dissimilis, Ptychoparia sp. ?, Arethusina Americana, lllamu- 

 rus sp. ?. Of this fauna two species are identical with those 

 from the higher Potsdam fauna at Eureka, viz : Ptychoparia 

 (E f) dissimilis and Arethusina f Americana • and Bellero- 

 phon antiquatus and Dicellocephalus Pepinensis occur in the 

 Upper Potsdam sandstone of Wisconsin. The presence of the 

 Pleurotomaria-like shells and the species just mentioned corre- 

 lates the fauna with that of the upper horizon of the Potsdam 

 faunas of "Wisconsin and Nevada.* 



From the data mentioned I am led to the conclusion that the 

 Mt. Stephens fauna described by Dr. Pominger should be re- 

 ferred to about the horizon of the upper portion of the Middle 

 Cambrian fauna. This correlation, united with the discovery 

 of the Olenellus fauna by Dr. George M. Dawson, in 1885, near 

 Kicking Horse Pass, on the line of the Canadian Pacific rail- 

 way, leads me to think that the Middle Cambrian fauna will be 

 found to extend all along the western side of the great Kewee- 

 nawan continental area, from Southern Nevada far into British 

 America, and that that area will be found to belong to one 

 geologic and faunal province of the Cambrian system. f 



As Dr. Pominger has described nearly all the forms from 

 Mt. Stephens as new to science it is necessary for me to review 

 his work, since I have otherwise identified them in my work 

 on the Middle Cambrian fauna. ;£ 



He describes^tlie new genus, Embolimus, and SiYe new 

 species of trilobites, viz : Ogygia Klotzi, 0. serrata, Emboli- 

 mus spinosa, E. rotundata and Conocephalites Cordillerai. 

 He also identifies Monocephalus Salteri f Billings, Bathyu- 

 rusf, Agnostus ("compare A. integer Barr.") and the genera 

 Orthis, Obolella, Kutorgina, Leptsena?, Metoptoma and Hyo- 

 lithes. y 



Eywolimus. — The generic name Embolimus was given by 

 Westwood to a genus of Hymenoptera in 1833. § It was 

 spelled Embokmus by Westwood and was corrected by Pro- 

 fessor Agassiz in the Nomeuclator Zoologicus 



The first species named under this genus by Dr. Pominger, 

 Embolimus spinosa, was described as Olenoides spinosus in 



* Loc. cit., p. 35. 



\ This Journal, III, vol. xxxiii, pp. 139-157, 1886. 



i U. S. Geol. Survey. Bull. No. 30, 1886. 



§ Phil. Mag., II, 1833. 



